Segments Of Business (Schedule Of Segments Of Business) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024
Segment Reporting Information [Line Items]
Electric utility revenues	$ 853	$ 791
Gas utility revenues	240	205
Other revenues	35	35
Total revenues	1,128	1,031
Electric production fuel and purchased power	175	163
Electric transmission service	158	152
Cost of gas sold	137	114
Other operation and maintenance	160	160
Depreciation and amortization	211	189
Interest expense	119	107
Equity income from unconsolidated investments, net	(13)	(15)
Income tax expense (benefit)	(47)	(10)
Other	15	13
Net income (loss)	213	158
Total assets	22,851	21,248	$ 22,714
Investments in equity method subsidiaries	633	594
Construction and acquisition expenditures	582	510
IPL [Member]
Segment Reporting Information [Line Items]
Electric utility revenues	430	392
Gas utility revenues	118	108
Total revenues	560	513
Electric production fuel and purchased power	67	67
Electric transmission service	108	103
Cost of gas sold	65	60
Depreciation and amortization	115	96
Income tax expense (benefit)	(40)	(10)
Net income (loss)	110	63
Total assets	11,540		11,407
WPL [Member]
Segment Reporting Information [Line Items]
Electric utility revenues	423	399
Gas utility revenues	122	97
Total revenues	546	496
Electric production fuel and purchased power	108	96
Electric transmission service	50	49
Cost of gas sold	72	53
Depreciation and amortization	93	90
Income tax expense (benefit)	(5)	6
Net income (loss)	110	92
Total assets	10,101		$ 10,106
Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Electric utility revenues	853	791
Gas utility revenues	240	205
Other revenues	13	13
Total revenues	1,106	1,009
Electric production fuel and purchased power	175	163
Electric transmission service	158	152
Cost of gas sold	137	113
Other operation and maintenance	149	149
Depreciation and amortization	208	186
Interest expense	90	83
Equity income from unconsolidated investments, net	0	0
Income tax expense (benefit)	(45)	(4)
Other	14	12
Net income (loss)	220	155
Total assets	21,641	20,113
Investments in equity method subsidiaries	22	21
Construction and acquisition expenditures	554	478
IPL [Member]
Segment Reporting Information [Line Items]
Electric utility revenues	430	392
Gas utility revenues	118	108
Other revenues	12	13
Total revenues	560	513
Electric production fuel and purchased power	67	67
Electric transmission service	108	103
Cost of gas sold	65	60
Other operation and maintenance	82	86
Depreciation and amortization	115	96
Interest expense	47	42
Equity income from unconsolidated investments, net	0	0
Income tax expense (benefit)	(40)	(10)
Other	6	6
Net income (loss)	110	63
Total assets	11,540	10,532
Investments in equity method subsidiaries	5	5
Construction and acquisition expenditures	376	253
WPL [Member]
Segment Reporting Information [Line Items]
Electric utility revenues	423	399
Gas utility revenues	122	97
Other revenues	1	0
Total revenues	546	496
Electric production fuel and purchased power	108	96
Electric transmission service	50	49
Cost of gas sold	72	53
Other operation and maintenance	67	63
Depreciation and amortization	93	90
Interest expense	43	41
Equity income from unconsolidated investments, net	0	0
Income tax expense (benefit)	(5)	6
Other	8	6
Net income (loss)	110	92
Total assets	10,101	9,581
Investments in equity method subsidiaries	17	16
Construction and acquisition expenditures	178	225
Other [Member]
Segment Reporting Information [Line Items]
Other revenues	22	22
Total revenues	22	22
Other operation and maintenance	11	11
Depreciation and amortization	3	3
Interest expense	29	24
Equity income from unconsolidated investments, net	(13)	(15)
Income tax expense (benefit)	(2)	(6)
Other	1	2
Net income (loss)	(7)	3
Total assets	1,210	1,135
Investments in equity method subsidiaries	611	573
Construction and acquisition expenditures	$ 28	$ 32