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v3.24.0.1

Effects of Regulation (Details) - USD ($) $ in Millions | 1 Months Ended | 12 Months Ended
--- | --- | ---
Feb. 26, 2024 | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
Regulated Generating Unit to be Retired |  |  |  |  |
Net Investment |  |  | $ 76,693.4 | $ 73,339.1 |
Materials and Supplies |  |  | 1,025.8 | 915.1 |
Annual Depreciation |  |  | 2,927.5 | 3,072.8 | $ 2,717.1
Regulatory Assets |  |  |  |  |
Current Regulatory Assets |  |  | 514.0 | 1,310.0 |
Noncurrent Regulatory Assets |  |  | 5,092.4 | 4,762.0 |
Regulatory Liabilities |  |  |  |  |
Current Regulatory Liabilities |  |  | 26.5 | 1.4 |
Noncurrent Regulatory Liabilities |  |  | 8,182.4 | 8,115.6 |
Effects of Regulation Textuals [Abstract] |  |  |  |  |
Revisions in Cash Flow Estimates | [1],[2],[3],[4],[5],[6],[7] |  | 63.0 | 100.3 |
Secured Debt |  |  | 368.9 | 487.8 |
Accumulated Depreciation and Amortization |  |  | 24,553.0 | 23,682.3 |
Asset Impairments and Other Related Charges |  |  | 85.6 | 48.8 | 11.6
Net Investment |  |  | 76,693.4 | 73,339.1 |
AEP Texas Inc. [Member] |  |  |  |  |
Regulated Generating Unit to be Retired |  |  |  |  |
Net Investment |  |  | 12,774.0 | 11,681.6 |
Materials and Supplies |  |  | 190.4 | 138.8 |
Annual Depreciation |  |  | 380.0 | 363.5 | 327.2
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 315.3 | 298.3 |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 1,261.4 | 1,259.6 |
Effects of Regulation Textuals [Abstract] |  |  |  |  |
Revisions in Cash Flow Estimates | [3],[4],[6] |  | 0.1 | 0.0 |
Secured Debt |  |  | 221.8 | 314.4 |
Accumulated Depreciation and Amortization |  |  | 1,887.9 | 1,760.7 |
Net Investment |  |  | 12,774.0 | 11,681.6 |
AEP Transmission Co [Member] |  |  |  |  |
Regulated Generating Unit to be Retired |  |  |  |  |
Net Investment |  |  | 14,497.7 | 13,339.9 |
Materials and Supplies |  |  | 0.0 | 10.7 |
Annual Depreciation |  |  | 393.8 | 346.2 | 297.3
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 3.1 | 7.2 |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 783.7 | 723.3 |
Effects of Regulation Textuals [Abstract] |  |  |  |  |
Accumulated Depreciation and Amortization |  |  | 1,291.3 | 1,027.0 |
Net Investment |  |  | 14,497.7 | 13,339.9 |
Appalachian Power Co [Member] |  |  |  |  |
Regulated Generating Unit to be Retired |  |  |  |  |
Net Investment |  |  | 12,931.5 | 12,379.2 |
Materials and Supplies |  |  | 148.4 | 130.6 |
Annual Depreciation |  |  | 571.1 | 576.1 | 547.0
Regulatory Assets |  |  |  |  |
Current Regulatory Assets |  |  | 155.4 | 473.1 |
Noncurrent Regulatory Assets |  |  | 1,155.1 | 1,058.6 |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 1,081.9 | 1,143.6 |
Effects of Regulation Textuals [Abstract] |  |  |  |  |
Revisions in Cash Flow Estimates | [3],[4],[6] |  | 26.5 | 17.0 |
Secured Debt |  |  | 147.0 | 173.3 |
Accumulated Depreciation and Amortization |  |  | 5,688.7 | 5,402.0 |
Asset Impairments and Other Related Charges |  |  | 0.0 | 24.9 | 0.0
Net Investment |  |  | 12,931.5 | 12,379.2 |
Indiana Michigan Power Co [Member] |  |  |  |  |
Regulated Generating Unit to be Retired |  |  |  |  |
Net Investment |  |  | 7,629.0 | 7,411.5 |
Materials and Supplies |  |  | 208.2 | 188.1 |
Annual Depreciation |  |  | 439.8 | 511.9 | 424.9
Regulatory Assets |  |  |  |  |
Current Regulatory Assets |  |  | 14.8 | 47.1 |
Noncurrent Regulatory Assets |  |  | 406.3 | 459.6 |
Regulatory Liabilities |  |  |  |  |
Current Regulatory Liabilities |  |  | 23.2 | 0.0 |
Noncurrent Regulatory Liabilities |  |  | 2,052.3 | 1,702.2 |
Effects of Regulation Textuals [Abstract] |  |  |  |  |
Revisions in Cash Flow Estimates | [3],[4],[5],[6] |  | 2.0 | 7.7 |
Accumulated Depreciation and Amortization |  |  | 4,378.4 | 4,132.8 |
Net Investment |  |  | 7,629.0 | 7,411.5 |
Ohio Power Co [Member] |  |  |  |  |
Regulated Generating Unit to be Retired |  |  |  |  |
Net Investment |  |  | 9,299.9 | 8,609.3 |
Materials and Supplies |  |  | 175.0 | 109.5 |
Annual Depreciation |  |  | 315.8 | 293.1 | 301.1
Regulatory Assets |  |  |  |  |
Current Regulatory Assets |  |  | 0.0 | 3.8 |
Noncurrent Regulatory Assets |  |  | 455.0 | 327.3 |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 1,003.6 | 1,044.0 |
Effects of Regulation Textuals [Abstract] |  |  |  |  |
Revisions in Cash Flow Estimates | [4],[6] |  | 0.0 | 0.0 |
Accumulated Depreciation and Amortization |  |  | 2,713.6 | 2,565.3 |
Net Investment |  |  | 9,299.9 | 8,609.3 |
Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulated Generating Unit to be Retired |  |  |  |  |
Net Investment |  |  | 6,112.3 | 5,626.5 |
Materials and Supplies |  |  | 106.9 | 111.1 |
Annual Depreciation |  |  | 240.3 | 226.2 | 185.9
Regulatory Assets |  |  |  |  |
Current Regulatory Assets |  |  | 118.3 | 178.7 |
Noncurrent Regulatory Assets |  |  | 522.7 | 653.7 |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 765.6 | 809.1 |
Effects of Regulation Textuals [Abstract] |  |  |  |  |
Revisions in Cash Flow Estimates | [1],[3],[4],[6] |  | (0.8) | 1.9 |
Accumulated Depreciation and Amortization |  |  | 2,081.9 | 1,837.7 |
Net Investment |  |  | 6,112.3 | 5,626.5 |
Southwestern Electric Power Co [Member] |  |  |  |  |
Regulated Generating Unit to be Retired |  |  |  |  |
Net Investment |  |  | 8,558.4 | 8,262.2 |
Materials and Supplies |  |  | 88.4 | 92.1 |
Annual Depreciation |  |  | 323.4 | 319.3 | 292.9
Regulatory Assets |  |  |  |  |
Current Regulatory Assets |  |  | 170.8 | 353.0 |
Noncurrent Regulatory Assets |  |  | 1,131.8 | 1,042.4 |
Regulatory Liabilities |  |  |  |  |
Current Regulatory Liabilities |  |  | 3.3 | 1.4 |
Noncurrent Regulatory Liabilities |  |  | 756.1 | 825.7 |
Effects of Regulation Textuals [Abstract] |  |  |  |  |
Revisions in Cash Flow Estimates | [1],[2],[3],[4],[6] |  | 34.5 | 56.7 |
Accumulated Depreciation and Amortization |  |  | 3,087.2 | 3,527.3 |
Asset Impairments and Other Related Charges |  |  | 85.6 | 0.0 | $ 11.6
Net Investment |  |  | 8,558.4 | 8,262.2 |
Net Under-Recovered Fuel Costs |  |  | 77.0 |  |
Regulatory Liabilities Approved for Payment [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 7,974.5 | 7,961.8 |
Regulatory Liabilities Approved for Payment [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 1,246.9 | 1,244.8 |
Regulatory Liabilities Approved for Payment [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 1,054.3 | 1,113.1 |
Regulatory Liabilities Approved for Payment [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 2,132.5 | 1,789.9 |
Regulatory Liabilities Approved for Payment [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 946.4 | 1,043.8 |
Regulatory Liabilities Approved for Payment [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 764.4 | 757.8 |
Regulatory Liabilities Approved for Payment [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 749.1 | 818.7 |
Regulatory Liabilities Pending Final Regulatory Determination [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 207.9 | 153.8 |
Regulatory Liabilities Pending Final Regulatory Determination [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 14.5 | 14.8 |
Regulatory Liabilities Pending Final Regulatory Determination [Member] | AEP Transmission Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 8.7 | 8.7 |
Regulatory Liabilities Pending Final Regulatory Determination [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 27.6 | 30.5 |
Regulatory Liabilities Pending Final Regulatory Determination [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | (80.2) | (87.7) |
Regulatory Liabilities Pending Final Regulatory Determination [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 57.2 | 0.2 |
Regulatory Liabilities Pending Final Regulatory Determination [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 1.2 | 51.3 |
Regulatory Liabilities Pending Final Regulatory Determination [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 7.0 | 7.0 |
Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 5,823.1 | 5,983.4 |
Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 1,212.9 | 1,202.7 |
Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | AEP Transmission Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 775.0 | 714.6 |
Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 1,000.0 | 1,005.1 |
Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 311.6 | 365.5 |
Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 883.7 | 918.4 |
Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 713.2 | 696.4 |
Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 740.0 | 811.0 |
Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Pending Final Regulatory Determination [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 103.1 | 149.7 |
Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Pending Final Regulatory Determination [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 13.0 | 13.0 |
Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Pending Final Regulatory Determination [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 7.9 | 30.5 |
Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Pending Final Regulatory Determination [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | (103.0) | (87.7) |
Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Pending Final Regulatory Determination [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 0.0 | 51.3 |
Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 2,151.4 | 1,978.4 |
Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 34.0 | 42.1 |
Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 54.3 | 108.0 |
Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 1,820.9 | 1,424.4 |
Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 62.7 | 125.4 |
Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 51.2 | 61.4 |
Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 9.1 | 7.7 |
Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Pending Final Regulatory Determination [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 104.8 | 4.1 |
Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Pending Final Regulatory Determination [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 1.5 | 1.8 |
Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Pending Final Regulatory Determination [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 19.7 | 0.0 |
Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Pending Final Regulatory Determination [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 22.8 | 0.0 |
Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Pending Final Regulatory Determination [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 1.2 | 0.0 |
Regulatory Assets Pending Final Regulatory Approval [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 837.3 | 882.1 |
Regulatory Assets Pending Final Regulatory Approval [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 64.3 | 67.0 |
Regulatory Assets Pending Final Regulatory Approval [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 125.5 | 144.5 |
Regulatory Assets Pending Final Regulatory Approval [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 33.2 | 23.7 |
Regulatory Assets Pending Final Regulatory Approval [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 23.6 | 33.8 |
Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 407.8 | 510.2 |
Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 4,255.1 | 3,879.9 |
Regulatory Assets Approved for Recovery [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 251.0 | 231.3 |
Regulatory Assets Approved for Recovery [Member] | AEP Transmission Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 3.1 | 7.2 |
Regulatory Assets Approved for Recovery [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 1,029.6 | 914.1 |
Regulatory Assets Approved for Recovery [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 373.1 | 435.9 |
Regulatory Assets Approved for Recovery [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 431.4 | 293.5 |
Regulatory Assets Approved for Recovery [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 434.0 | 628.1 |
Regulatory Assets Approved for Recovery [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 724.0 | 532.2 |
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 349.9 | 355.6 |
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 0.0 | 17.6 |
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 0.6 | 7.0 |
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 0.2 | 0.1 |
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 338.1 | 330.9 |
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 1,946.9 | 1,858.6 |
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 43.5 | 17.5 |
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 340.3 | 299.3 |
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 229.3 | 270.6 |
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 44.0 | 34.9 |
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 325.3 | 552.8 |
Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 483.1 | 321.8 |
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 487.4 | 526.5 |
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 64.3 | 49.4 |
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 124.9 | 137.5 |
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 33.0 | 23.6 |
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 88.7 | 25.6 |
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 69.7 | 179.3 |
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 2,308.2 | 2,021.3 |
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 207.5 | 213.8 |
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 689.3 | 614.8 |
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 143.8 | 165.3 |
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 387.4 | 258.6 |
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 108.7 | 75.3 |
Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 240.9 | 210.4 |
Northeastern Plant, Unit 3 [Member] | Generating Units Probable of Abandonment [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulated Generating Unit to be Retired |  |  |  |  |
Net Investment |  |  | 104.5 |  |
Accelerated Depreciation Regulatory Asset |  |  | 164.2 |  |
Cost of Removal Regulatory Liability | [8] |  | $ 20.5 |  |
Expected Retirement Date | [9] |  | 2026 |  |
Annual Depreciation | [10] |  | $ 15.0 |  |
Effects of Regulation Textuals [Abstract] |  |  |  |  |
Net Investment |  |  | 104.5 |  |
Pirkey Power Plant [Member] | Southwestern Electric Power Co [Member] | TEXAS |  |  |  |  |
Regulated Generating Unit to be Retired |  |  |  |  |
Net Investment |  |  | 67.0 |  |
Effects of Regulation Textuals [Abstract] |  |  |  |  |
Net Investment |  |  | 67.0 |  |
Welsh Plant, Units 1 and 3 [Member] | Generating Units Probable of Abandonment [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulated Generating Unit to be Retired |  |  |  |  |
Net Investment |  |  | 352.0 |  |
Accelerated Depreciation Regulatory Asset |  |  | 125.6 |  |
Cost of Removal Regulatory Liability | [11] |  | $ 58.2 |  |
Expected Retirement Date | [12],[13] |  | 2028 |  |
Annual Depreciation | [10] |  | $ 38.6 |  |
Effects of Regulation Textuals [Abstract] |  |  |  |  |
Net Investment |  |  | 352.0 |  |
Deferred Fuel Costs [Member] | Regulatory Liabilities Currently Paying a Return [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Current Regulatory Liabilities |  |  | $ 3.3 | 1.4 |
Remaining Refund Period |  |  | 1 year |  |
Deferred Fuel Costs [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Current Regulatory Liabilities | [14] |  | $ 3.3 | 1.4 |
Remaining Refund Period |  |  | 1 year |  |
Deferred Fuel Costs [Member] | Regulatory Liabilities Currently Not Paying Return [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Current Regulatory Liabilities |  |  | $ 23.2 | 0.0 |
Remaining Refund Period |  |  | 1 year |  |
Deferred Fuel Costs [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Indiana Michigan Power Co [Member] | Indiana |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Current Regulatory Liabilities |  |  | $ 23.2 | 0.0 |
Remaining Refund Period |  |  | 1 year |  |
Deferred Fuel Costs [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | $ 26.1 | 32.2 |
Remaining Refund Period |  |  | 9 years |  |
Deferred Fuel Costs [Member] | Regulatory Assets Currently Earning Return [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Current Regulatory Assets |  |  | $ 357.4 | 625.7 |
Remaining Recovery Period |  |  | 1 year |  |
Deferred Fuel Costs [Member] | Regulatory Assets Currently Earning Return [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Current Regulatory Assets |  |  | $ 147.4 | 180.7 |
Remaining Recovery Period |  |  | 1 year |  |
Deferred Fuel Costs [Member] | Regulatory Assets Currently Earning Return [Member] | Indiana Michigan Power Co [Member] | Michigan |  |  |  |  |
Regulatory Assets |  |  |  |  |
Current Regulatory Assets |  |  | $ 14.8 | 9.0 |
Remaining Recovery Period |  |  | 1 year |  |
Deferred Fuel Costs [Member] | Regulatory Assets Currently Earning Return [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Current Regulatory Assets |  |  | $ 118.3 | 178.7 |
Remaining Recovery Period |  |  | 1 year |  |
Deferred Fuel Costs [Member] | Regulatory Assets Currently Earning Return [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Current Regulatory Assets | [15] |  | $ 76.9 | 257.2 |
Remaining Recovery Period |  |  | 1 year |  |
Deferred Fuel Costs [Member] | Regulatory Assets Currently Not Earning Return [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Current Regulatory Assets |  |  | $ 62.7 | 588.5 |
Remaining Recovery Period |  |  | 1 year |  |
Deferred Fuel Costs [Member] | Regulatory Assets Currently Not Earning Return [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Current Regulatory Assets |  |  | $ 8.0 | 292.4 |
Remaining Recovery Period |  |  | 1 year |  |
Deferred Fuel Costs [Member] | Regulatory Assets Currently Not Earning Return [Member] | Indiana Michigan Power Co [Member] | Indiana |  |  |  |  |
Regulatory Assets |  |  |  |  |
Current Regulatory Assets |  |  | $ 0.0 | 38.1 |
Deferred Fuel Costs [Member] | Regulatory Assets Currently Not Earning Return [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Current Regulatory Assets |  |  | $ 0.0 | 3.8 |
Remaining Recovery Period |  |  | 1 year |  |
Dolet Hills Power Station Accelerated Depreciation [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets | [16] |  | $ 12.0 | 9.7 |
Kentucky Deferred Purchase Power Expenses [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 43.5 | 53.0 |
Remaining Recovery Period |  |  | 4 years |  |
Pirkey Power Plant Accelerated Depreciation [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 114.4 | 116.5 |
Pirkey Power Plant Accelerated Depreciation [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 114.4 | 116.5 |
Pirkey Power Plant Accelerated Depreciation [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Louisiana Jurisdiction [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 65.8 | 63.0 |
Remaining Recovery Period |  |  | 9 years |  |
Pirkey Power Plant Accelerated Depreciation [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Southwestern Electric Power Co [Member] | Louisiana Jurisdiction [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 65.8 | 63.0 |
Remaining Recovery Period |  |  | 9 years |  |
Welsh Plant, Units 1 and 3 Accelerated Depreciation [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 125.6 | 85.6 |
Welsh Plant, Units 1 and 3 Accelerated Depreciation [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 125.6 | 85.6 |
Other Regulatory Assets Pending Final Regulatory Approval [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 49.8 | 68.9 |
Other Regulatory Assets Pending Final Regulatory Approval [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 0.6 | 7.0 |
Other Regulatory Assets Pending Final Regulatory Approval [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 0.2 | 0.1 |
Other Regulatory Assets Pending Final Regulatory Approval [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 26.0 | 34.5 |
Other Regulatory Assets Pending Final Regulatory Approval [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 78.5 | 81.5 |
Other Regulatory Assets Pending Final Regulatory Approval [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 11.7 | 8.9 |
Other Regulatory Assets Pending Final Regulatory Approval [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 7.5 | 1.1 |
Other Regulatory Assets Pending Final Regulatory Approval [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 3.3 | 2.0 |
Other Regulatory Assets Pending Final Regulatory Approval [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 0.2 | 0.1 |
Other Regulatory Assets Pending Final Regulatory Approval [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 13.7 | 16.0 |
Storm Related Costs [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 170.9 | 8.4 |
Remaining Recovery Period |  |  | 5 years |  |
Storm Related Costs [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 26.2 | 8.4 |
Remaining Recovery Period |  |  | 5 years |  |
Storm Related Costs [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Southwestern Electric Power Co [Member] | Louisiana Jurisdiction [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 144.7 | 0.0 |
Remaining Recovery Period |  |  | 2 years |  |
Storm Related Costs [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 408.9 | 407.1 |
Storm Related Costs [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 37.7 | 26.7 |
Storm Related Costs [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 91.5 | 72.6 |
Storm Related Costs [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 29.7 | 21.6 |
Storm Related Costs [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 23.6 | 33.8 |
Storm Related Costs [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 88.5 | 25.5 |
Storm Related Costs [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 56.0 | 151.5 |
Storm Related Costs [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 38.5 | 11.9 |
Remaining Recovery Period |  |  | 2 years |  |
Storm Related Costs [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 4.3 | 8.5 |
Remaining Recovery Period |  |  | 2 years |  |
Storm Related Costs [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 30.9 | 0.0 |
Remaining Recovery Period |  |  | 1 year |  |
Plant Retirement Costs - Asset Retirement Obligation Costs [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 110.8 | 110.6 |
Remaining Recovery Period |  |  | 19 years |  |
Plant Retirement Costs - Asset Retirement Obligation Costs [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 25.9 | 25.9 |
Plant Retirement Costs - Asset Retirement Obligation Costs [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 330.2 | 308.5 |
Remaining Recovery Period |  |  | 19 years |  |
Plant Retirement Costs - Asset Retirement Obligation Costs [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 324.7 | 303.1 |
Remaining Recovery Period |  |  | 15 years |  |
Vegetation Management Program [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 5.2 | 5.2 |
Vegetation Management Program [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 6.8 | 12.1 |
Remaining Recovery Period |  |  | 2 years |  |
Plant Retirement Costs - Unrecovered Plant [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets | [17] |  | $ 664.2 | 689.9 |
Remaining Recovery Period |  |  | 23 years |  |
Plant Retirement Costs - Unrecovered Plant [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 72.0 | 75.6 |
Remaining Recovery Period |  |  | 20 years |  |
Plant Retirement Costs - Unrecovered Plant [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 122.5 | 147.0 |
Remaining Recovery Period |  |  | 5 years |  |
Plant Retirement Costs - Unrecovered Plant [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets | [18] |  | $ 254.1 | 240.6 |
Remaining Recovery Period |  |  | 23 years |  |
Plant Retirement Costs - Unrecovered Plant, Arkansas [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 44.4 | 13.1 |
Remaining Recovery Period |  |  | 19 years |  |
Plant Retirement Costs - Unrecovered Plant, Arkansas [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 17.3 | 21.1 |
Remaining Recovery Period |  |  | 4 years |  |
Plant Retirement Costs - Unrecovered Plant, Texas [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 48.7 | 51.7 |
Remaining Recovery Period |  |  | 23 years |  |
Plant Retirement Costs - Unrecovered Plant, Texas [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 48.7 | 51.7 |
Remaining Recovery Period |  |  | 23 years |  |
Meter Replacement Costs [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 23.5 | 34.2 |
Remaining Recovery Period |  |  | 4 years |  |
Meter Replacement Costs [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 9.4 | 16.1 |
Remaining Recovery Period |  |  | 2 years |  |
Meter Replacement Costs [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 14.1 | 18.1 |
Remaining Recovery Period |  |  | 4 years |  |
Ohio Distribution Decoupling [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 1.8 | 19.5 |
Remaining Recovery Period |  |  | 2 years |  |
Ohio Basic Transmission Cost Rider [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 42.2 | 14.3 |
Remaining Recovery Period |  |  | 2 years |  |
Ohio Basic Transmission Cost Rider [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 42.2 | 14.3 |
Remaining Recovery Period |  |  | 2 years |  |
Environmental Controls Projects [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 31.4 | 33.9 |
Remaining Recovery Period |  |  | 17 years |  |
Environmental Controls Projects [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 22.5 | 23.9 |
Remaining Recovery Period |  |  | 17 years |  |
Environmental Controls Projects [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 8.9 | 10.0 |
Remaining Recovery Period |  |  | 9 years |  |
Rockport Plant Dry Sorbent Injection System and Selective Catalytic Reduction [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 46.9 | 56.6 |
Remaining Recovery Period |  |  | 5 years |  |
Rockport Plant Dry Sorbent Injection System and Selective Catalytic Reduction [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 46.9 | 56.6 |
Remaining Recovery Period |  |  | 5 years |  |
Cook Plant Uprate Project [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 22.9 | 25.3 |
Remaining Recovery Period |  |  | 10 years |  |
Other Regulatory Assets Approved for Recovery [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 101.4 | 125.0 |
Other Regulatory Assets Approved for Recovery [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 0.7 | 1.4 |
Other Regulatory Assets Approved for Recovery [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 7.1 | 0.4 |
Other Regulatory Assets Approved for Recovery [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 17.5 | 20.6 |
Other Regulatory Assets Approved for Recovery [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 8.4 | 9.1 |
Other Regulatory Assets Approved for Recovery [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 4.9 | 6.8 |
Other Regulatory Assets Approved for Recovery [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 271.5 | 262.7 |
Other Regulatory Assets Approved for Recovery [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 4.0 | 8.1 |
Other Regulatory Assets Approved for Recovery [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 17.5 | 12.3 |
Other Regulatory Assets Approved for Recovery [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 21.0 | 19.7 |
Other Regulatory Assets Approved for Recovery [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 11.6 | 14.9 |
Other Regulatory Assets Approved for Recovery [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 16.2 | 20.1 |
Other Regulatory Assets Approved for Recovery [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 30.1 | 35.0 |
Asset Retirement Obligation - Louisiana [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 0.0 | 11.8 |
Deferred Cook Plant Life Cycle Management Project Costs [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 11.1 | 12.1 |
Remaining Recovery Period |  |  | 11 years |  |
Cook Plant Turbine [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 8.4 | 9.0 |
Remaining Recovery Period |  |  | 15 years |  |
Pension Costs [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 1,054.1 | 975.4 |
Remaining Recovery Period |  |  | 12 years |  |
Pension Costs [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 183.2 | 173.2 |
Remaining Recovery Period |  |  | 12 years |  |
Pension Costs [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 115.8 | 108.3 |
Remaining Recovery Period |  |  | 12 years |  |
Pension Costs [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 25.4 | 26.9 |
Remaining Recovery Period |  |  | 12 years |  |
Pension Costs [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 147.1 | 142.7 |
Remaining Recovery Period |  |  | 12 years |  |
Pension Costs [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 62.6 | 55.2 |
Remaining Recovery Period |  |  | 12 years |  |
Pension Costs [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 109.2 | 96.2 |
Remaining Recovery Period |  |  | 12 years |  |
Unamortized Loss on Reacquired Debt [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 97.2 | 104.1 |
Remaining Recovery Period |  |  | 25 years |  |
Unamortized Loss on Reacquired Debt [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 70.7 | 74.4 |
Remaining Recovery Period |  |  | 22 years |  |
Unamortized Loss on Reacquired Debt [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 11.8 | 12.9 |
Remaining Recovery Period |  |  | 25 years |  |
Peak Demand Reduction/Energy Efficiency [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 9.2 | 11.9 |
Remaining Recovery Period |  |  | 2 years |  |
Peak Demand Reduction/Energy Efficiency [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 15.0 | 15.8 |
Remaining Recovery Period |  |  | 3 years |  |
Unrealized Loss on Forward Commitments [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 131.4 | 40.1 |
Remaining Recovery Period |  |  | 9 years |  |
Unrealized Loss on Forward Commitments [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 21.9 | 0.0 |
Remaining Recovery Period |  |  | 3 years |  |
Unrealized Loss on Forward Commitments [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 50.8 | 40.0 |
Remaining Recovery Period |  |  | 9 years |  |
Unrealized Loss on Forward Commitments [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 29.9 | 0.0 |
Remaining Recovery Period |  |  | 2 years |  |
Unrealized Loss on Forward Commitments [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 15.4 | 0.0 |
Remaining Recovery Period |  |  | 2 years |  |
Virginia Transmission Rate Adjustment Clause [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 25.5 | 18.7 |
Remaining Recovery Period |  |  | 2 years |  |
Vegetation Management Program - West Virginia [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 12.9 | 13.7 |
Remaining Recovery Period |  |  | 2 years |  |
Cook Nuclear Plant Refueling Outage Levelization [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 55.7 | 81.2 |
Remaining Recovery Period |  |  | 2 years |  |
Cook Nuclear Plant Refueling Outage Levelization [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 55.7 | 81.2 |
Remaining Recovery Period |  |  | 2 years |  |
PJM/SPP Annual Formula Rate True Up [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | AEP Transmission Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 3.1 | 7.2 |
Remaining Recovery Period |  |  | 2 years |  |
Postemployment Benefits [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 30.6 | 32.1 |
Remaining Recovery Period |  |  | 3 years |  |
Postemployment Benefits [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 14.9 | 13.7 |
Remaining Recovery Period |  |  | 3 years |  |
Postemployment Benefits [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 7.0 | 7.7 |
Remaining Recovery Period |  |  | 3 years |  |
OVEC Purchased Power [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | $ 0.0 | 47.1 |
OVEC Purchased Power [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 0.0 | 47.1 |
OVEC Purchased Power [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 50.1 | 0.0 |
Remaining Recovery Period |  |  | 2 years |  |
OVEC Purchased Power [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 50.1 | 0.0 |
Remaining Recovery Period |  |  | 2 years |  |
Fuel and Purchased Power Adjustment Rider [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 68.3 | 76.3 |
Remaining Recovery Period |  |  | 2 years |  |
PJM Costs and Off-system Sales Margin Sharing - Indiana [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | $ 14.1 | 34.2 |
Remaining Refund Period |  |  | 2 years |  |
PJM Costs and Off-system Sales Margin Sharing - Indiana [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | $ 14.1 | 34.2 |
Remaining Refund Period |  |  | 2 years |  |
Other Regulatory Liabilities Pending Final Regulatory Determination [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Pending Final Regulatory Determination [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | $ 1.7 | 4.1 |
Other Regulatory Liabilities Pending Final Regulatory Determination [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Pending Final Regulatory Determination [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 1.5 | 1.8 |
Other Regulatory Liabilities Pending Final Regulatory Determination [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Pending Final Regulatory Determination [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 0.2 | 0.2 |
Excess ADIT that is Not Subject to Rate Normalization Requirements [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | $ 228.0 | 277.0 |
Remaining Refund Period |  |  | 5 years |  |
Excess ADIT that is Not Subject to Rate Normalization Requirements [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | AEP Transmission Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | $ 13.0 | 16.0 |
Remaining Refund Period |  |  | 5 years |  |
Excess ADIT that is Not Subject to Rate Normalization Requirements [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | $ 35.0 | 19.0 |
Remaining Refund Period |  |  | 5 years |  |
Excess ADIT that is Not Subject to Rate Normalization Requirements [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | $ 25.0 | 42.0 |
Remaining Refund Period |  |  | 5 years |  |
Excess ADIT that is Not Subject to Rate Normalization Requirements [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | $ 132.0 | 162.0 |
Remaining Refund Period |  |  | 5 years |  |
Excess ADIT that is Not Subject to Rate Normalization Requirements [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | $ 51.0 | 21.0 |
Remaining Refund Period |  |  | 1 year |  |
Asset Removal Costs [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities | [19] |  | $ 3,563.5 | 3,392.4 |
Asset Removal Costs [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities | [20] |  | 797.1 | 766.8 |
Asset Removal Costs [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | AEP Transmission Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities | [21] |  | 466.3 | 358.8 |
Asset Removal Costs [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities | [22] |  | 759.6 | 713.5 |
Asset Removal Costs [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities | [23] |  | 168.1 | 170.7 |
Asset Removal Costs [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities | [24] |  | 475.5 | 466.5 |
Asset Removal Costs [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities | [25] |  | 317.5 | 316.3 |
Asset Removal Costs [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities | [26] |  | 443.2 | 481.2 |
Deferred Investment Tax Credits [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | $ 0.3 | 0.3 |
Remaining Refund Period |  |  | 30 years |  |
Deferred Investment Tax Credits [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | $ 154.5 | 237.3 |
Remaining Refund Period |  |  | 31 years |  |
Deferred Investment Tax Credits [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | $ 15.8 | 17.4 |
Remaining Refund Period |  |  | 27 years |  |
Deferred Investment Tax Credits [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | $ 47.2 | 48.2 |
Remaining Refund Period |  |  | 18 years |  |
Other Regulatory Liabilities Approved for Payment [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | $ 35.0 | 32.7 |
Other Regulatory Liabilities Approved for Payment [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 3.8 | 4.3 |
Other Regulatory Liabilities Approved for Payment [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 0.1 | 3.0 |
Other Regulatory Liabilities Approved for Payment [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 4.4 | 2.2 |
Other Regulatory Liabilities Approved for Payment [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 96.0 | 129.2 |
Other Regulatory Liabilities Approved for Payment [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 7.4 | 12.7 |
Other Regulatory Liabilities Approved for Payment [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 14.6 | 20.8 |
Other Regulatory Liabilities Approved for Payment [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 4.8 | 8.5 |
Other Regulatory Liabilities Approved for Payment [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 3.6 | 7.8 |
Other Regulatory Liabilities Approved for Payment [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 4.0 | 13.2 |
Other Regulatory Liabilities Approved for Payment [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 9.1 | 7.7 |
Excess Nuclear Decommissioning Funding [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities | [27] |  | 1,721.9 | 1,318.5 |
Excess Nuclear Decommissioning Funding [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities | [28] |  | 1,721.9 | 1,318.5 |
PJM Transmission Enhancement Refund [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | $ 22.8 | 34.1 |
Remaining Refund Period |  |  | 2 years |  |
PJM Transmission Enhancement Refund [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | $ 9.8 | 14.7 |
Remaining Refund Period |  |  | 2 years |  |
Transition and Restoration Charges [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | $ 26.6 | 29.4 |
Remaining Refund Period |  |  | 6 years |  |
2017-2019 Virginia Triennial Revenue Provision [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | $ 37.1 | 39.1 |
Remaining Refund Period |  |  | 26 years |  |
2017-2019 Virginia Triennial Revenue Provision [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | $ 37.1 | 39.1 |
Remaining Refund Period |  |  | 26 years |  |
2017-2019 Virginia Triennial Revenue Provision [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 2.3 | 30.1 |
Remaining Recovery Period |  |  | 1 year |  |
Spent Nuclear Fuel [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities | [27] |  | $ 47.6 | 45.8 |
Spent Nuclear Fuel [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities | [28] |  | 47.6 | 45.8 |
Peak Demand Reduction/Energy Efficiency [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | $ 23.2 | 23.6 |
Remaining Refund Period |  |  | 2 years |  |
Peak Demand Reduction/Energy Efficiency [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 23.9 | 41.7 |
Remaining Recovery Period |  |  | 3 years |  |
Peak Demand Reduction/Energy Efficiency [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 0.0 | 10.3 |
Ohio Enhanced Service Reliability Plan [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 35.3 | 33.3 |
Remaining Recovery Period |  |  | 2 years |  |
Ohio Enhanced Service Reliability Plan [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 35.3 | 33.3 |
Remaining Recovery Period |  |  | 2 years |  |
Smart Grid Costs [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 26.3 | 25.4 |
Remaining Recovery Period |  |  | 2 years |  |
Distribution Investment Rider [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 35.3 | 2.3 |
Remaining Recovery Period |  |  | 2 years |  |
Distribution Investment Rider [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 35.3 | 2.3 |
Remaining Recovery Period |  |  | 2 years |  |
Dolet Hills Generating Station and Related Fuel Operations | Southwestern Electric Power Co [Member] |  |  |  |  |
Effects of Regulation Textuals [Abstract] |  |  |  |  |
Share of Net Investment in Dolet Hills Power Station |  |  | $ 103.0 |  |
Dolet Hills Generating Station and Related Fuel Operations | Southwestern Electric Power Co [Member] | TEXAS |  |  |  |  |
Effects of Regulation Textuals [Abstract] |  |  |  |  |
Oxbow Mine Related Costs Recovery Request |  |  | 48.0 |  |
Dolet Hills Generating Station and Related Fuel Operations | Southwestern Electric Power Co [Member] | Arkansas |  |  |  |  |
Effects of Regulation Textuals [Abstract] |  |  |  |  |
Amount of Dolet Hills Fuel Costs Approved to Recover |  |  | 20.0 |  |
Dolet Hills Generating Station and Related Fuel Operations | Southwestern Electric Power Co [Member] | Louisiana Jurisdiction [Member] |  |  |  |  |
Effects of Regulation Textuals [Abstract] |  |  |  |  |
Amount of Dolet Hills Fuel Costs Approved to Recover |  |  | 20.0 |  |
Approved Deferral of Dolet Hills Fuel Costs |  |  | 35.0 |  |
Recommended Dolet Hills Fuel Disallowance |  |  | 55.0 |  |
Dolet Hills Generating Station and Related Fuel Operations | Southwestern Electric Power Co [Member] | Louisiana Jurisdiction [Member] | Subsequent Event [Member] |  |  |  |  |
Effects of Regulation Textuals [Abstract] |  |  |  |  |
ALJ Recommended Customer Refund |  | $ 55.0 |  |  |
ALJ Recommended Denial of Recovery for Fuel Costs Deferral |  | $ 35.0 |  |  |
Pirkey Power Plant and Related Fuel Operations | Southwestern Electric Power Co [Member] |  |  |  |  |
Effects of Regulation Textuals [Abstract] |  |  |  |  |
Share of Net Investment in Pirkey Power Plant |  |  | 182.0 |  |
Pirkey Power Plant and Related Fuel Operations | Southwestern Electric Power Co [Member] | TEXAS |  |  |  |  |
Effects of Regulation Textuals [Abstract] |  |  |  |  |
Oxbow Mine Related Costs Recovery Request |  |  | 33.0 |  |
Dolet Hills Power Station [Member] | Southwestern Electric Power Co [Member] | TEXAS |  |  |  |  |
Effects of Regulation Textuals [Abstract] |  |  |  |  |
Asset Impairments and Other Related Charges |  |  | 12.0 |  |
Dolet Hills Power Station [Member] | Southwestern Electric Power Co [Member] | Arkansas |  |  |  |  |
Effects of Regulation Textuals [Abstract] |  |  |  |  |
Asset Impairments and Other Related Charges |  |  | 2.0 |  |
Unrealized Gain on Forward Commitments [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 0.0 | 45.2 |
Unrealized Gain on Forward Commitments [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 0.0 | 34.5 |
February 2021 Severe Storm Fuel Costs | Regulatory Assets Currently Earning Return [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Current Regulatory Assets | [29] |  | $ 93.9 | 95.8 |
Remaining Recovery Period |  |  | 1 year |  |
February 2021 Severe Storm Fuel Costs | Regulatory Assets Currently Earning Return [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Current Regulatory Assets | [30] |  | $ 93.9 | 95.8 |
Remaining Recovery Period |  |  | 1 year |  |
February 2021 Severe Storm Fuel Costs | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets | [29] |  | $ 60.1 | 84.6 |
February 2021 Severe Storm Fuel Costs | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets | [30] |  | 60.1 | 84.6 |
February 2021 Severe Storm Fuel Costs | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets | [29] |  | $ 99.3 | 148.6 |
Remaining Recovery Period |  |  | 4 years |  |
February 2021 Severe Storm Fuel Costs | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets | [30] |  | $ 99.3 | 148.6 |
Remaining Recovery Period |  |  | 4 years |  |
Texas Retail Electric Provider Bad Debt Expense | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 4.0 | 4.1 |
Environmental Cost Rider - Indiana | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 8.1 | 6.6 |
Remaining Recovery Period |  |  | 2 years |  |
Ohio Economic Development Rider | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 0.0 | 1.1 |
2020-2022 Virginia Triennial Under-Earnings [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 0.0 | 37.9 |
2020-2022 Virginia Triennial Under-Earnings [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 0.0 | 37.9 |
2020-2022 Virginia Triennial Under-Earnings [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 37.4 | 0.0 |
Remaining Recovery Period |  |  | 4 years |  |
2020-2022 Virginia Triennial Under-Earnings [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 37.4 | 0.0 |
Remaining Recovery Period |  |  | 4 years |  |
Long-term Under-recovered Fuel Costs - Oklahoma [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 0.0 | 252.7 |
Long-term Under-recovered Fuel Costs - Oklahoma [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 0.0 | 252.7 |
Long-term Under-recovered Fuel Costs - Virginia [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 107.0 | 223.3 |
Remaining Recovery Period |  |  | 2 years |  |
Long-term Under-recovered Fuel Costs - Virginia [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 107.0 | 223.3 |
Remaining Recovery Period |  |  | 2 years |  |
Plant Retirement Costs - Unrecovered Plant, Dolet Hills Power Station [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Louisiana Jurisdiction [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 40.8 | 45.1 |
Remaining Recovery Period |  |  | 9 years |  |
Plant Retirement Costs - Unrecovered Plant, Dolet Hills Power Station [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Southwestern Electric Power Co [Member] | Louisiana Jurisdiction [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 40.8 | 45.1 |
Remaining Recovery Period |  |  | 9 years |  |
Income Taxes, Net [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities | [31],[32] |  | $ 2,179.7 | 2,504.5 |
Income Taxes, Net [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities | [33],[34] |  | 412.0 | 431.6 |
Income Taxes, Net [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | AEP Transmission Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities | [35],[36] |  | 308.7 | 355.8 |
Income Taxes, Net [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities | [37],[38] |  | 240.1 | 291.3 |
Income Taxes, Net [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities | [39],[40] |  | 116.8 | 168.6 |
Income Taxes, Net [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities | [41],[42] |  | 408.2 | 451.9 |
Income Taxes, Net [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities | [43],[44] |  | 395.7 | 380.1 |
Income Taxes, Net [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities | [45],[46] |  | 292.4 | 327.6 |
Income Taxes, Net [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Pending Final Regulatory Determination [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities | [31] |  | 103.1 | 149.7 |
Income Taxes, Net [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Pending Final Regulatory Determination [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities | [33] |  | 13.0 | 13.0 |
Income Taxes, Net [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Pending Final Regulatory Determination [Member] | AEP Transmission Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities | [35] |  | 8.7 | 8.7 |
Income Taxes, Net [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Pending Final Regulatory Determination [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities | [37] |  | 7.9 | 30.5 |
Income Taxes, Net [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Pending Final Regulatory Determination [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities | [40],[47] |  | (103.0) | (87.7) |
Income Taxes, Net [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Pending Final Regulatory Determination [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities | [44] |  | 0.0 | 51.3 |
Income Taxes, Net [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Pending Final Regulatory Determination [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities | [45] |  | 7.0 | 7.0 |
Rockport Plant, Unit 2 Accelerated Depreciation for Leasehold Improvements [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | $ 44.9 | 53.8 |
Remaining Refund Period |  |  | 5 years |  |
Renewable Energy Surcharge - Michigan [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | $ 26.6 | 23.2 |
Remaining Refund Period |  |  | 2 years |  |
Over-recovered Fuel Costs - Ohio [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | $ 26.1 | 32.2 |
Remaining Refund Period |  |  | 9 years |  |
Texas Mobile Generation Lease Payments [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 0.0 | 17.6 |
Texas Mobile Generation Lease Payments [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 33.4 | 0.0 |
Remaining Recovery Period |  |  | 2 years |  |
Virginia Clean Economy Act [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 8.0 | 16.7 |
Remaining Recovery Period |  |  | 2 years |  |
Over-recovered Deferred Wind Costs - Virginia [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | $ 2.6 | 13.6 |
Remaining Refund Period |  |  | 2 years |  |
Plant Retirement Costs - Unrecovered Plant, Welsh Plant, Unit 2 [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Southwestern Electric Power Co [Member] | Louisiana Jurisdiction [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 0.0 | 35.2 |
Line Inspection Costs [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Pending Final Regulatory Approval [Member] | AEP Texas Inc. [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | 5.7 | 4.5 |
Long-term Under-Recovered Fuel Costs - West Virginia [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 291.5 | 0.0 |
Remaining Recovery Period |  |  | 11 years |  |
Long-term Under-Recovered Fuel Costs - West Virginia [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 154.2 | 0.0 |
Remaining Recovery Period |  |  | 11 years |  |
Fuel Mine Closure Costs - Texas [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 74.3 | 0.0 |
Remaining Recovery Period |  |  | 12 years |  |
Fuel Mine Closure Costs - Texas [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Southwestern Electric Power Co [Member] | Louisiana Jurisdiction [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 74.3 | 0.0 |
Remaining Recovery Period |  |  | 12 years |  |
Texas Mobile Temporary Emergency Electric Energy Facilities Rider [Member] | Regulatory Assets Currently Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Louisiana Jurisdiction [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 33.4 | 0.0 |
Remaining Recovery Period |  |  | 2 years |  |
Demand Side Management [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | $ 31.3 | 15.7 |
Remaining Refund Period |  |  | 2 years |  |
Demand Side Management [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Approved for Payment [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | $ 16.7 | 0.0 |
Remaining Refund Period |  |  | 2 years |  |
FERC 2021 Transmission Formula Rate Challenge Refunds [Member] | Regulatory Liabilities Currently Paying a Return [Member] | Regulatory Liabilities Pending Final Regulatory Determination [Member] | Public Service Co Of Oklahoma [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | $ 1.2 | 0.0 |
FERC 2021 Transmission Formula Rate Challenge Refunds [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Pending Final Regulatory Determination [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 103.1 | 0.0 |
FERC 2021 Transmission Formula Rate Challenge Refunds [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Pending Final Regulatory Determination [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 19.7 | 0.0 |
FERC 2021 Transmission Formula Rate Challenge Refunds [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Pending Final Regulatory Determination [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 22.8 | 0.0 |
FERC 2021 Transmission Formula Rate Challenge Refunds [Member] | Regulatory Liabilities Currently Not Paying Return [Member] | Regulatory Liabilities Pending Final Regulatory Determination [Member] | Ohio Power Co [Member] |  |  |  |  |
Regulatory Liabilities |  |  |  |  |
Noncurrent Regulatory Liabilities |  |  | 57.0 | 0.0 |
Excess SO2 Allowance Inventory - Virginia [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 11.8 | 0.0 |
Remaining Recovery Period |  |  | 9 years |  |
Excess SO2 Allowance Inventory - Virginia [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Indiana Michigan Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 14.8 | 0.0 |
Remaining Recovery Period |  |  | 5 years |  |
Virginia Generation Rate Adjustment Clause [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Appalachian Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 10.9 | 8.0 |
Remaining Recovery Period |  |  | 2 years |  |
North Central Wind Rider [Member] | Regulatory Assets Currently Not Earning Return [Member] | Regulatory Assets Approved for Recovery [Member] | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 20.2 | 6.4 |
Remaining Recovery Period |  |  | 2 years |  |
February 2021 Severe Storm Fuel Costs | Southwestern Electric Power Co [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 253.3 | 329.0 |
February 2021 Severe Storm Fuel Costs | Southwestern Electric Power Co [Member] | Arkansas |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 54.2 | 74.9 |
Remaining Recovery Period |  |  | 6 years |  |
February 2021 Severe Storm Fuel Costs | Southwestern Electric Power Co [Member] | Louisiana Jurisdiction [Member] |  |  |  |  |
Regulatory Assets |  |  |  |  |
Noncurrent Regulatory Assets |  |  | $ 97.2 | $ 121.7 |
[1] | Includes ARO related to wind farms.
[2] | Includes ARO related to Sabine and DHLC.
[3] | Includes ARO related to ash disposal facilities.
[4] | Includes ARO related to asbestos removal.
[5] | Includes ARO related to nuclear decommissioning costs for the Cook Plant of $2.11 billion and $2 billion as of December 31, 2023 and 2022, respectively.
[6] | Unless discussed above, primarily related to ash ponds, landfills and mine reclamation, generally due to changes in estimated closure area, volumes and/or unit costs.
[7] | Includes ARO related to solar farms.
[8] | Includes Northeastern Plant, Unit 4, which was retired in 2016. Removal of Northeastern Plant, Unit 4, will be performed with the removal of Northeastern Plant, Unit 3, after retirement.
[9] | Northeastern Plant, Unit 3 is currently being recovered through 2040.
[10] | Represents the amount of annual depreciation that has been collected from customers over the prior 12-month period.
[11] | Includes Welsh Plant, Unit 2, which was retired in 2016. Removal of Welsh Plant, Unit 2, will be performed with the removal of Welsh Plant, Units 1 and 3, after retirement.
[12] | Represents projected retirement date of coal assets, units are being evaluated for conversion to natural gas after 2028.
[13] | Unit 1 is being recovered through 2027 in the Louisiana jurisdiction and through 2037 in the Arkansas and Texas jurisdictions. Unit 3 is being recovered through 2032 in the Louisiana jurisdiction and through 2042 in the Arkansas and Texas jurisdictions.
[14] | Amounts include Louisiana jurisdiction.
[15] | Amounts include Arkansas and Texas jurisdictions.
[16] | Amounts include the FERC jurisdiction.
[17] | Northeastern Plant, Unit 3 is approved for recovery through 2040, but expected to retire in 2026. PSO records a regulatory asset for accelerated depreciation. See “Regulated Generating Units to be Retired” section above for additional information.
[18] | Northeastern Plant, Unit 3 is approved for recovery through 2040, but expected to retire in 2026. PSO records a regulatory asset for accelerated depreciation. See “Regulated Generating Units to be Retired” section above for additional information.
[19] | Relieved as removal costs are incurred.
[20] | Relieved as removal costs are incurred.
[21] | Relieved as removal costs are incurred.
[22] | Relieved as removal costs are incurred.
[23] | Relieved as removal costs are incurred.
[24] | Relieved as removal costs are incurred.
[25] | Relieved as removal costs are incurred.
[26] | Relieved as removal costs are incurred.
[27] | Relieved when plant is decommissioned.
[28] | Relieved when plant is decommissioned.
[29] | See “February 2021 Severe Winter Weather Impacts in SPP” section of SWEPCo Rate Matters in Note 4 for additional information.
[30] | See “February 2021 Severe Winter Weather Impacts in SPP” section of SWEPCo Rate Matters in Note 4 for additional information.
[31] | Predominately pays a return due to the inclusion of Excess ADIT in rate base.
[32] | Refunded over the period for which the related deferred income tax reverse, which is generally based on the expected life for the underlying assets. Excess ADIT Associated with Certain Depreciable Property is refunded over the remaining depreciable life of the underlying assets. Excess ADIT that is Not Subject to Rate Normalization Requirements were $228 million and $277 million for the years ended December 31, 2023 and 2022, respectively. The remaining balance of Excess ADIT that is Not Subject to Rate Normalization Requirements as of December 31, 2023 is to be refunded over 5 years.
[33] | Predominately pays a return due to the inclusion of Excess ADIT in rate base.
[34] | Refunded over the period for which the related deferred income tax reverse, which is generally based on the expected life for the underlying assets. Excess ADIT Associated with Certain Depreciable Property is refunded over the remaining depreciable life of the underlying assets.
[35] | Predominately pays a return due to the inclusion of Excess ADIT in rate base.
[36] | Refunded over the period for which the related deferred income tax reverse, which is generally based on the expected life for the underlying assets. Excess ADIT Associated with Certain Depreciable Property is refunded over the remaining depreciable life of the underlying assets. Excess ADIT that is Not Subject to Rate Normalization Requirements were $13 million and $16 million for the years ended December 31, 2023 and 2022, respectively. The remaining balance of Excess ADIT that is Not Subject to Rate Normalization Requirements as of December 31, 2023 is to be refunded over 5 years.
[37] | Predominately pays a return due to the inclusion of Excess ADIT in rate base.
[38] | Refunded over the period for which the related deferred income tax reverse, which is generally based on the expected life for the underlying assets. Excess ADIT Associated with Certain Depreciable Property is refunded over the remaining depreciable life of the underlying assets. Excess ADIT that is Not Subject to Rate Normalization Requirements were $35 million and $19 million for the years ended December 31, 2023 and 2022, respectively. The remaining balance of Excess ADIT that is Not Subject to Rate Normalization Requirements as of December 31, 2023 is to be refunded over 5 years.
[39] | Refunded over the period for which the related deferred income tax reverse, which is generally based on the expected life for the underlying assets. Excess ADIT Associated with Certain Depreciable Property is refunded over the remaining depreciable life of the underlying assets. Excess ADIT that is Not Subject to Rate Normalization Requirements were $25 million and $42 million for the years ended December 31, 2023 and 2022, respectively. The remaining balance of Excess ADIT that is Not Subject to Rate Normalization Requirements as of December 31, 2023 is to be refunded over 5 years.
[40] | Predominately pays a return due to the inclusion of Excess ADIT in rate base.
[41] | Predominately pays a return due to the inclusion of Excess ADIT in rate base.
[42] | Refunded over the period for which the related deferred income tax reverse, which is generally based on the expected life for the underlying assets. Excess ADIT Associated with Certain Depreciable Property is refunded over the remaining depreciable life of the underlying assets. Excess ADIT that is Not Subject to Rate Normalization Requirements were $132 million and $162 million for the years ended December 31, 2023 and 2022, respectively. The remaining balance of Excess ADIT that is Not Subject to Rate Normalization Requirements as of December 31, 2023 is to be refunded over 5 years.
[43] | Refunded over the period for which the related deferred income tax reverse, which is generally based on the expected life for the underlying assets. Excess ADIT Associated with Certain Depreciable Property is refunded over the remaining depreciable life of the underlying assets. Excess ADIT that is Not Subject to Rate Normalization Requirements were $51 million and $21 million for the years ended December 31, 2023 and 2022, respectively. The remaining balance of Excess ADIT that is Not Subject to Rate Normalization Requirements as of December 31, 2023 is to be refunded over 1 year.
[44] | Predominately pays a return due to the inclusion of Excess ADIT in rate base.
[45] | Predominately pays a return due to the inclusion of Excess ADIT in rate base.
[46] | Refunded over the period for which the related deferred income tax reverse, which is generally based on the expected life for the underlying assets. Excess ADIT Associated with Certain Depreciable Property is refunded over the remaining depreciable life of the underlying assets.
[47] | Represents an income tax related regulatory asset, which is presented within net regulatory liabilities on the balance sheet.

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