Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 13	$ 20
Accounts receivable, less allowance for expected credit losses	428	516
Production fuel, at weighted average cost	64	53
Gas stored underground, at weighted average cost	69	132
Materials and supplies, at weighted average cost	172	140
Regulatory assets	196	166
Other	196	223
Total current assets	1,138	1,250
Property, plant and equipment, net	16,306	16,247
Investments:
ATC Holdings	372	358
Other	212	201
Total investments	584	559
Other assets:
Regulatory assets	2,148	1,880
Deferred charges and other	207	227
Total other assets	2,355	2,107
Total assets	20,383	20,163
Current liabilities:
Current maturities of long-term debt	409	408
Commercial paper	391	642
Other short-term borrowings	50	0
Accounts payable	585	756
Regulatory liabilities	121	206
Other	337	351
Total current liabilities	1,893	2,363
Long-term debt, net (excluding current portion)	8,186	7,668
Other liabilities:
Deferred tax liabilities	1,969	1,943
Regulatory liabilities	1,087	1,118
Pension and other benefit obligations	262	277
Other	534	518
Total other liabilities	3,852	3,856
Commitments and contingencies (Note 13)
Common equity:
Common stock	3	3
Additional paid-in capital	2,854	2,777
Retained earnings	3,606	3,509
Accumulated other comprehensive income	3	0
Shares in deferred compensation trust - 405,051 and 402,134 shares at a weighted average cost of $33.69 and $32.63 per share	(14)	(13)
Total common equity	6,452	6,276
Total liabilities and equity	20,383	20,163
IPL [Member]
Current assets:
Cash and cash equivalents	9	15
Accounts receivable, less allowance for expected credit losses	204	259
Production fuel, at weighted average cost	31	23
Gas stored underground, at weighted average cost	27	60
Materials and supplies, at weighted average cost	100	83
Regulatory assets	90	85
Other	78	93
Total current assets	539	618
Property, plant and equipment, net	7,923	8,046
Other assets:
Regulatory assets	1,558	1,301
Deferred charges and other	101	110
Total other assets	1,659	1,411
Total assets	10,121	10,075
Current liabilities:
Accounts payable	247	239
Accounts payable to associated companies	40	28
Accrued taxes	51	52
Accrued interest	35	35
Regulatory liabilities	73	114
Other	97	113
Total current liabilities	543	581
Long-term debt, net (excluding current portion)	3,702	3,646
Other liabilities:
Deferred tax liabilities	1,061	1,047
Regulatory liabilities	603	640
Pension and other benefit obligations	60	62
Other	283	291
Total other liabilities	2,007	2,040
Commitments and contingencies (Note 13)
Common equity:
Common stock	33	33
Additional paid-in capital	2,847	2,807
Retained earnings	989	968
Total common equity	3,869	3,808
Total liabilities and equity	10,121	10,075
WPL [Member]
Current assets:
Cash and cash equivalents	3	5
Accounts receivable, less allowance for expected credit losses	210	244
Production fuel, at weighted average cost	33	29
Gas stored underground, at weighted average cost	42	73
Materials and supplies, at weighted average cost	70	54
Regulatory assets	106	81
Prepaid gross receipts tax	47	42
Other	47	60
Total current assets	558	588
Property, plant and equipment, net	7,882	7,722
Other assets:
Regulatory assets	590	579
Deferred charges and other	69	98
Total other assets	659	677
Total assets	9,099	8,987
Current liabilities:
Commercial paper	44	290
Accounts payable	277	456
Regulatory liabilities	48	92
Other	140	111
Total current liabilities	509	949
Long-term debt, net (excluding current portion)	3,068	2,770
Other liabilities:
Deferred tax liabilities	785	789
Regulatory liabilities	484	478
Pension and other benefit obligations	127	140
Other	387	370
Total other liabilities	1,783	1,777
Commitments and contingencies (Note 13)
Common equity:
Common stock	66	66
Additional paid-in capital	2,413	2,233
Retained earnings	1,260	1,192
Total common equity	3,739	3,491
Total liabilities and equity	$ 9,099	$ 8,987