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INCOME TAXES - Temporary Differences That Give Rise To Accumulated Deferred Income Tax Obligations (Details) - USD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2023 | Dec. 31, 2022
Deferred Tax Assets: |  |
Employee Benefits | $ 244.5 | $ 228.9
Derivative Liabilities | 33.0 | 53.8
Regulatory Deferrals - Liabilities | 452.0 | 529.5
Allowance for Uncollectible Accounts | 143.8 | 125.5
Tax Effect - Tax Regulatory Liabilities | 739.0 | 762.9
Net Operating Loss Carryforwards | 13.8 | 16.7
Purchase Accounting Adjustment | 56.7 | 62.0
Equity Method Wind Investments | 584.9 | 0.0
Other | 200.1 | 176.6
Total Deferred Tax Assets | 2,467.8 | 1,955.9
Less: Valuation Allowance | 328.1 | 82.8
Net Deferred Tax Assets | 2,139.7 | 1,873.1
Deferred Tax Liabilities: |  |
Accelerated Depreciation and Other Plant-Related Differences | 5,103.3 | 4,793.7
Property Tax Accruals | 95.0 | 95.3
Regulatory Amounts: |  |
Regulatory Deferrals - Assets | 1,512.3 | 1,251.9
Tax Effect - Tax Regulatory Assets | 284.0 | 271.7
Goodwill-related Regulatory Asset - 1999 Merger | 72.2 | 76.8
Employee Benefits | 282.0 | 305.5
Derivative Assets | 6.4 | 10.5
Other | 88.2 | 135.6
Total Deferred Tax Liabilities | 7,443.4 | 6,941.0
Offshore Wind Business |  |
Regulatory Amounts: |  |
Impairment charge | 224.0 |
CL&P |  |
Deferred Tax Assets: |  |
Employee Benefits | 29.9 | 25.3
Derivative Liabilities | 33.0 | 53.8
Regulatory Deferrals - Liabilities | 94.4 | 146.6
Allowance for Uncollectible Accounts | 79.6 | 60.5
Tax Effect - Tax Regulatory Liabilities | 320.7 | 324.6
Net Operating Loss Carryforwards | 0.0 | 0.0
Purchase Accounting Adjustment | 0.0 | 0.0
Equity Method Wind Investments | 0.0 | 0.0
Other | 125.3 | 109.5
Total Deferred Tax Assets | 682.9 | 720.3
Less: Valuation Allowance | 80.6 | 63.3
Net Deferred Tax Assets | 602.3 | 657.0
Deferred Tax Liabilities: |  |
Accelerated Depreciation and Other Plant-Related Differences | 1,703.4 | 1,602.0
Property Tax Accruals | 42.0 | 40.7
Regulatory Amounts: |  |
Regulatory Deferrals - Assets | 470.0 | 406.4
Tax Effect - Tax Regulatory Assets | 191.9 | 185.6
Goodwill-related Regulatory Asset - 1999 Merger | 0.0 | 0.0
Employee Benefits | 38.8 | 45.0
Derivative Assets | 6.4 | 10.5
Other | 9.9 | 6.8
Total Deferred Tax Liabilities | 2,462.4 | 2,297.0
NSTAR Electric |  |
Deferred Tax Assets: |  |
Employee Benefits | 66.8 | 57.4
Derivative Liabilities | 0.0 | 0.0
Regulatory Deferrals - Liabilities | 291.5 | 285.7
Allowance for Uncollectible Accounts | 21.5 | 20.7
Tax Effect - Tax Regulatory Liabilities | 227.1 | 241.8
Net Operating Loss Carryforwards | 0.0 | 0.0
Purchase Accounting Adjustment | 0.0 | 0.0
Equity Method Wind Investments | 0.0 | 0.0
Other | 25.0 | 20.5
Total Deferred Tax Assets | 631.9 | 626.1
Less: Valuation Allowance | 0.0 | 0.0
Net Deferred Tax Assets | 631.9 | 626.1
Deferred Tax Liabilities: |  |
Accelerated Depreciation and Other Plant-Related Differences | 1,728.6 | 1,643.7
Property Tax Accruals | 39.8 | 41.3
Regulatory Amounts: |  |
Regulatory Deferrals - Assets | 474.5 | 407.9
Tax Effect - Tax Regulatory Assets | 10.5 | 10.7
Goodwill-related Regulatory Asset - 1999 Merger | 61.9 | 65.9
Employee Benefits | 146.7 | 140.8
Derivative Assets | 0.0 | 0.0
Other | 19.5 | 16.7
Total Deferred Tax Liabilities | 2,481.5 | 2,327.0
PSNH |  |
Deferred Tax Assets: |  |
Employee Benefits | 13.0 | 11.6
Derivative Liabilities | 0.0 | 0.0
Regulatory Deferrals - Liabilities | 23.8 | 42.1
Allowance for Uncollectible Accounts | 3.9 | 7.9
Tax Effect - Tax Regulatory Liabilities | 95.5 | 97.8
Net Operating Loss Carryforwards | 0.0 | 0.0
Purchase Accounting Adjustment | 0.0 | 0.0
Equity Method Wind Investments | 0.0 | 0.0
Other | 23.4 | 21.3
Total Deferred Tax Assets | 159.6 | 180.7
Less: Valuation Allowance | 0.0 | 0.0
Net Deferred Tax Assets | 159.6 | 180.7
Deferred Tax Liabilities: |  |
Accelerated Depreciation and Other Plant-Related Differences | 566.5 | 523.8
Property Tax Accruals | 6.3 | 6.7
Regulatory Amounts: |  |
Regulatory Deferrals - Assets | 250.3 | 165.2
Tax Effect - Tax Regulatory Assets | 8.3 | 7.9
Goodwill-related Regulatory Asset - 1999 Merger | 0.0 | 0.0
Employee Benefits | 16.8 | 18.7
Derivative Assets | 0.0 | 0.0
Other | 2.9 | 21.2
Total Deferred Tax Liabilities | $ 851.1 | $ 743.5

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