Segments Of Business (Schedule Of Segments Of Business) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Segment Reporting Information [Line Items]
Revenues	$ 912	$ 943	$ 1,990	$ 2,012
Operating income	217	212	439	460
Net income (loss) attributable to common shareowners	160	159	323	351
Net income			323	351
IPL [Member]
Segment Reporting Information [Line Items]
Revenues	487	506	1,037	1,056
Operating income	110	109	206	218
Net income	89	87	161	173
WPL [Member]
Segment Reporting Information [Line Items]
Revenues	402	413	908	909
Operating income	99	95	220	227
Net income	72	63	160	156
Electric [Member]
Segment Reporting Information [Line Items]
Revenues	799	812	1,567	1,586
Operating income	200	195	363	376
Electric [Member] | IPL [Member]
Segment Reporting Information [Line Items]
Revenues	431	442	819	843
Operating income	105	104	171	179
Electric [Member] | WPL [Member]
Segment Reporting Information [Line Items]
Revenues	368	370	748	743
Operating income	95	91	192	197
Gas [Member]
Segment Reporting Information [Line Items]
Revenues	77	94	353	356
Operating income	2	8	52	65
Gas [Member] | IPL [Member]
Segment Reporting Information [Line Items]
Revenues	44	52	194	191
Operating income	0	4	27	36
Gas [Member] | WPL [Member]
Segment Reporting Information [Line Items]
Revenues	33	42	159	165
Operating income	2	4	25	29
Other Utility [Member]
Segment Reporting Information [Line Items]
Revenues	13	13	25	23
Operating income	7	1	11	4
Other Utility [Member] | IPL [Member]
Segment Reporting Information [Line Items]
Revenues	12	12	24	22
Operating income	5	1	8	3
Other Utility [Member] | WPL [Member]
Segment Reporting Information [Line Items]
Revenues	1	1	1	1
Operating income	2	0	3	1
Utility Business [Member]
Segment Reporting Information [Line Items]
Revenues	889	919	1,945	1,965
Operating income	209	204	426	445
Net income (loss) attributable to common shareowners	161	150	321	329
ATC Holdings, Non-Utility, Parent and Other [Member]
Segment Reporting Information [Line Items]
Revenues	23	24	45	47
Operating income	8	8	13	15
Net income (loss) attributable to common shareowners	$ (1)	$ 9	$ 2	$ 22