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v3.21.2

Segments Of Business (Schedule Of Segments Of Business) (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2021 | Sep. 30, 2020 | Sep. 30, 2021 | Sep. 30, 2020
Segment Reporting Information [Line Items] |  |  |  |
Revenues | $ 1,024 | $ 920 | $ 2,742 | $ 2,599
Operating income (loss) | 289 | 272 | 663 | 628
Net income attributable to common shareowners | 256 | 246 | 571 | 550
Net income | 259 | 249 | 579 | 558
IPL [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | 599 | 553 | 1,543 | 1,504
Operating income (loss) | 180 | 162 | 394 | 347
Net income attributable to common shareowners | 157 | 148 | 322 | 290
Net income | 160 | 151 | 330 | 298
WPL [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | 403 | 351 | 1,139 | 1,038
Operating income (loss) | 100 | 89 | 245 | 255
Net income | 93 | 73 | 215 | 220
Electric [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | 939 | 852 | 2,357 | 2,257
Operating income (loss) | 290 | 251 | 601 | 549
Electric [Member] | IPL [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | 555 | 519 | 1,343 | 1,332
Operating income (loss) | 186 | 159 | 365 | 308
Electric [Member] | WPL [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | 384 | 333 | 1,014 | 925
Operating income (loss) | 104 | 92 | 236 | 241
Gas [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | 50 | 42 | 289 | 253
Operating income (loss) | (5) | (1) | 42 | 48
Gas [Member] | IPL [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | 31 | 24 | 165 | 141
Operating income (loss) | (3) | 1 | 30 | 34
Gas [Member] | WPL [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | 19 | 18 | 124 | 112
Operating income (loss) | (2) | (2) | 12 | 14
Other Utility [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | 13 | 10 | 36 | 32
Operating income (loss) | (5) | 1 | (4) | 5
Other Utility [Member] | IPL [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | 13 | 10 | 35 | 31
Operating income (loss) | (3) | 2 | (1) | 5
Other Utility [Member] | WPL [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | 0 | 0 | 1 | 1
Operating income (loss) | (2) | (1) | (3) | 0
Utility Business [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | 1,002 | 904 | 2,682 | 2,542
Operating income (loss) | 280 | 251 | 639 | 602
Net income attributable to common shareowners | 250 | 221 | 537 | 510
Non-Utility [Member] | ATC Holdings, Non-Utility, Parent and Other [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenues | 22 | 16 | 60 | 57
Operating income (loss) | 9 | 21 | 24 | 26
Net income attributable to common shareowners | $ 6 | $ 25 | $ 34 | $ 40

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