Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 827	$ 62
Accounts receivable, less allowance for expected credit losses	463	475
Production fuel, at weighted average cost	60	62
Gas stored underground, at weighted average cost	60	79
Materials and supplies, at weighted average cost	200	202
Regulatory assets	214	232
Other	144	160
Total current assets	1,968	1,272
Property, plant and equipment, net	17,936	17,157
Investments:
ATC Holdings	407	386
Other	226	216
Total investments	633	602
Other assets:
Regulatory assets	2,136	2,029
Deferred charges and other	156	177
Total other assets	2,292	2,206
Total assets	22,829	21,237
Current liabilities:
Current maturities of long-term debt	1,104	809
Commercial paper	330	475
Accounts payable	473	611
Regulatory liabilities	81	107
Other	300	302
Total current liabilities	2,288	2,304
Long-term debt, net (excluding current portion)	9,245	8,225
Other liabilities:
Deferred tax liabilities	2,164	2,042
Regulatory liabilities	991	1,023
Pension and other benefit obligations	234	249
Other	939	617
Total other liabilities	4,328	3,931
Commitments and contingencies (Note 14)
Common equity:
Common stock	3	3
Additional paid-in capital	3,052	3,030
Retained earnings	3,927	3,756
Accumulated other comprehensive income (loss)	(1)	1
Shares in deferred compensation trust - 362,813 and 379,006 shares at a weighted average cost of $35.94 and $34.48 per share	(13)	(13)
Total common equity	6,968	6,777
Total liabilities and equity	22,829	21,237
IPL [Member]
Current assets:
Cash and cash equivalents	756	53
Accounts receivable, less allowance for expected credit losses	234	242
Production fuel, at weighted average cost	34	27
Gas stored underground, at weighted average cost	26	35
Materials and supplies, at weighted average cost	118	122
Regulatory assets	93	93
Other	71	51
Total current assets	1,332	623
Property, plant and equipment, net	8,801	8,298
Other assets:
Regulatory assets	1,475	1,484
Deferred charges and other	72	84
Total other assets	1,547	1,568
Total assets	11,680	10,489
Current liabilities:
Current maturities of long-term debt	800	500
Accounts payable	240	262
Accrued taxes	61	50
Accrued interest	45	40
Regulatory liabilities	34	72
Other	93	101
Total current liabilities	1,273	1,025
Long-term debt, net (excluding current portion)	3,789	3,445
Other liabilities:
Deferred tax liabilities	1,195	1,091
Regulatory liabilities	519	572
Pension and other benefit obligations	47	51
Other	437	331
Total other liabilities	2,198	2,045
Commitments and contingencies (Note 14)
Common equity:
Common stock	33	33
Additional paid-in capital	3,212	2,887
Retained earnings	1,175	1,054
Total common equity	4,420	3,974
Total liabilities and equity	11,680	10,489
WPL [Member]
Current assets:
Cash and cash equivalents	69	7
Accounts receivable, less allowance for expected credit losses	214	219
Production fuel, at weighted average cost	26	35
Gas stored underground, at weighted average cost	34	44
Materials and supplies, at weighted average cost	77	77
Regulatory assets	121	139
Prepaid gross receipts tax	37	49
Other	30	43
Total current assets	608	613
Property, plant and equipment, net	8,613	8,415
Other assets:
Regulatory assets	661	545
Deferred charges and other	56	61
Total other assets	717	606
Total assets	9,938	9,634
Current liabilities:
Commercial paper	0	318
Accounts payable	168	293
Accrued interest	41	40
Regulatory liabilities	47	35
Other	95	89
Total current liabilities	351	775
Long-term debt, net (excluding current portion)	3,369	3,070
Other liabilities:
Deferred tax liabilities	843	827
Regulatory liabilities	472	451
Pension and other benefit obligations	109	121
Other	719	493
Total other liabilities	2,143	1,892
Commitments and contingencies (Note 14)
Common equity:
Common stock	66	66
Additional paid-in capital	2,533	2,478
Retained earnings	1,476	1,353
Total common equity	4,075	3,897
Total liabilities and equity	$ 9,938	$ 9,634