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v3.21.1

Segments Of Business (Schedule Of Segments Of Business) (Details) - USD ($) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2021 | Mar. 31, 2020
Segment Reporting Information [Line Items] |  |
Revenues | $ 901 | $ 916
Operating income (loss) | 198 | 188
Net income (loss) attributable to common shareowners | 171 | 170
Net income | 174 | 173
IPL [Member] |  |
Segment Reporting Information [Line Items] |  |
Revenues | 489 | 519
Operating income (loss) | 103 | 97
Net income (loss) attributable to common shareowners | 79 | 83
Net income | 82 | 86
WPL [Member] |  |
Segment Reporting Information [Line Items] |  |
Revenues | 395 | 375
Operating income (loss) | 90 | 94
Net income | 84 | 90
Electric [Member] |  |
Segment Reporting Information [Line Items] |  |
Revenues | 701 | 730
Operating income (loss) | 147 | 146
Electric [Member] | IPL [Member] |  |
Segment Reporting Information [Line Items] |  |
Revenues | 386 | 425
Operating income (loss) | 72 | 67
Electric [Member] | WPL [Member] |  |
Segment Reporting Information [Line Items] |  |
Revenues | 315 | 305
Operating income (loss) | 75 | 79
Gas [Member] |  |
Segment Reporting Information [Line Items] |  |
Revenues | 170 | 152
Operating income (loss) | 44 | 41
Gas [Member] | IPL [Member] |  |
Segment Reporting Information [Line Items] |  |
Revenues | 91 | 83
Operating income (loss) | 30 | 27
Gas [Member] | WPL [Member] |  |
Segment Reporting Information [Line Items] |  |
Revenues | 79 | 69
Operating income (loss) | 14 | 14
Other Utility [Member] |  |
Segment Reporting Information [Line Items] |  |
Revenues | 13 | 12
Operating income (loss) | 2 | 4
Other Utility [Member] | IPL [Member] |  |
Segment Reporting Information [Line Items] |  |
Revenues | 12 | 11
Operating income (loss) | 1 | 3
Other Utility [Member] | WPL [Member] |  |
Segment Reporting Information [Line Items] |  |
Revenues | 1 | 1
Operating income (loss) | 1 | 1
Utility Business [Member] |  |
Segment Reporting Information [Line Items] |  |
Revenues | 884 | 894
Operating income (loss) | 193 | 191
Net income (loss) attributable to common shareowners | 163 | 173
Non-Utility [Member] | ATC Holdings, Non-Utility, Parent and Other [Member] |  |
Segment Reporting Information [Line Items] |  |
Revenues | 17 | 22
Operating income (loss) | 5 | (3)
Net income (loss) attributable to common shareowners | $ 8 | $ (3)

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