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Segments Of Business (Schedule Of Segment Of Business) (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
Segment Reporting Information [Line Items] |  |  |
Revenues | $ 4,027 | $ 4,205 | $ 3,669
Depreciation and amortization | 676 | 671 | 657
Operating income (loss) | 943 | 928 | 795
Interest expense | 394 | 325 | 277
Equity income from unconsolidated investments, net | (61) | (51) | (62)
Income tax expense (benefit) | 4 | 22 | (74)
Net income attributable to common shareowners | 703 | 686 | 659
Total assets | 21,237 | 20,163 | 18,553
Investments in equity method subsidiaries | 585 | 542 | 508
Construction and acquisition expenditures | 1,854 | 1,484 | 1,169
IPL [Member] |  |  |
Segment Reporting Information [Line Items] |  |  |
Revenues | 2,110 | 2,256 | 2,063
Operating income (loss) | 444 | 453 | 460
Interest expense | 155 | 148 | 139
Income tax expense (benefit) | (58) | (50) | (36)
Net income attributable to common shareowners | 366 | 360 | 350
Total assets | 10,489 | 10,075 |
WPL [Member] |  |  |
Segment Reporting Information [Line Items] |  |  |
Revenues | 1,827 | 1,856 | 1,523
Operating income (loss) | 472 | 452 | 308
Interest expense | 149 | 121 | 105
Income tax expense (benefit) | 60 | 66 | (51)
Total assets | 9,634 | 8,987 |
Electric [Member] |  |  |
Segment Reporting Information [Line Items] |  |  |
Revenues | 3,345 | 3,421 | 3,081
Depreciation and amortization | 602 | 601 | 591
Operating income (loss) | 827 | 805 | 716
Equity income from unconsolidated investments, net | (3) | (1) | (2)
Total assets | 17,833 | 16,571 | 14,924
Investments in equity method subsidiaries | 21 | 20 | 17
Construction and acquisition expenditures | 1,641 | 1,318 | 980
Electric [Member] | IPL [Member] |  |  |
Segment Reporting Information [Line Items] |  |  |
Revenues | 1,761 | 1,859 | 1,752
Depreciation and amortization | 348 | 342 | 338
Operating income (loss) | 390 | 397 | 420
Total assets | 9,311 | 8,686 | 8,602
Construction and acquisition expenditures | 671 | 336 | 342
Electric [Member] | WPL [Member] |  |  |
Segment Reporting Information [Line Items] |  |  |
Revenues | 1,584 | 1,562 | 1,329
Depreciation and amortization | 254 | 259 | 253
Operating income (loss) | 437 | 408 | 296
Total assets | 8,522 | 7,885 | 6,322
Construction and acquisition expenditures | 970 | 982 | 638
Gas [Member] |  |  |
Segment Reporting Information [Line Items] |  |  |
Revenues | 540 | 642 | 456
Depreciation and amortization | 60 | 56 | 54
Operating income (loss) | 70 | 97 | 63
Equity income from unconsolidated investments, net | 0 | 0 | 0
Total assets | 1,684 | 1,631 | 1,487
Investments in equity method subsidiaries | 0 | 0 | 0
Construction and acquisition expenditures | 90 | 74 | 90
Gas [Member] | IPL [Member] |  |  |
Segment Reporting Information [Line Items] |  |  |
Revenues | 300 | 351 | 265
Depreciation and amortization | 34 | 32 | 31
Operating income (loss) | 35 | 53 | 43
Total assets | 921 | 872 | 819
Construction and acquisition expenditures | 41 | 36 | 42
Gas [Member] | WPL [Member] |  |  |
Segment Reporting Information [Line Items] |  |  |
Revenues | 240 | 291 | 191
Depreciation and amortization | 26 | 24 | 23
Operating income (loss) | 35 | 44 | 20
Total assets | 763 | 759 | 668
Construction and acquisition expenditures | 49 | 38 | 48
Other Utility [Member] |  |  |
Segment Reporting Information [Line Items] |  |  |
Revenues | 52 | 49 | 49
Depreciation and amortization | 6 | 7 | 6
Operating income (loss) | 19 | 3 | (11)
Equity income from unconsolidated investments, net | 0 | 0 | 0
Total assets | 606 | 860 | 1,103
Investments in equity method subsidiaries | 0 | 0 | 0
Construction and acquisition expenditures | 0 | 0 | 0
Other Utility [Member] | IPL [Member] |  |  |
Segment Reporting Information [Line Items] |  |  |
Revenues | 49 | 46 | 46
Depreciation and amortization | 6 | 7 | 6
Operating income (loss) | 19 | 3 | (3)
Total assets | 257 | 517 | 575
Construction and acquisition expenditures | 0 | 0 | 0
Other Utility [Member] | WPL [Member] |  |  |
Segment Reporting Information [Line Items] |  |  |
Revenues | 3 | 3 | 3
Depreciation and amortization | 0 | 0 | 0
Operating income (loss) | 0 | 0 | (8)
Total assets | 349 | 343 | 528
Construction and acquisition expenditures | 0 | 0 | 0
ATC Holdings, Non-utility, Parent and Other [Member] |  |  |
Segment Reporting Information [Line Items] |  |  |
Revenues | 90 | 93 | 83
Depreciation and amortization | 8 | 7 | 6
Operating income (loss) | 27 | 23 | 27
Interest expense | 90 | 56 | 33
Equity income from unconsolidated investments, net | (58) | (50) | (60)
Income tax expense (benefit) | 2 | 6 | 13
Net income attributable to common shareowners | (8) | 11 | 41
Total assets | 1,114 | 1,101 | 1,039
Investments in equity method subsidiaries | 564 | 522 | 491
Construction and acquisition expenditures | 123 | 92 | 99
Utility Business [Member] |  |  |
Segment Reporting Information [Line Items] |  |  |
Revenues | 3,937 | 4,112 | 3,586
Depreciation and amortization | 668 | 664 | 651
Operating income (loss) | 916 | 905 | 768
Interest expense | 304 | 269 | 244
Equity income from unconsolidated investments, net | (3) | (1) | (2)
Income tax expense (benefit) | 2 | 16 | (87)
Net income attributable to common shareowners | 711 | 675 | 618
Total assets | 20,123 | 19,062 | 17,514
Investments in equity method subsidiaries | 21 | 20 | 17
Construction and acquisition expenditures | 1,731 | 1,392 | 1,070
Utility Business [Member] | IPL [Member] |  |  |
Segment Reporting Information [Line Items] |  |  |
Revenues | 2,110 | 2,256 | 2,063
Depreciation and amortization | 388 | 381 | 375
Operating income (loss) | 444 | 453 | 460
Interest expense | 155 | 148 | 139
Income tax expense (benefit) | (58) | (50) | (36)
Net income attributable to common shareowners | 366 | 360 | 350
Total assets | 10,489 | 10,075 | 9,996
Construction and acquisition expenditures | 712 | 372 | 384
Utility Business [Member] | WPL [Member] |  |  |
Segment Reporting Information [Line Items] |  |  |
Revenues | 1,827 | 1,856 | 1,523
Depreciation and amortization | 280 | 283 | 276
Operating income (loss) | 472 | 452 | 308
Interest expense | 149 | 121 | 105
Income tax expense (benefit) | 60 | 66 | (51)
Net income attributable to common shareowners | 345 | 315 | 268
Total assets | 9,634 | 8,987 | 7,518
Construction and acquisition expenditures | $ 1,019 | $ 1,020 | $ 686

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