Condensed Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Revenues:
Electric utility	$ 812	$ 717	$ 1,586	$ 1,418
Gas utility	94	69	356	239
Other utility	13	10	23	23
Non-utility	24	21	47	38
Total revenues	943	817	2,012	1,718
Operating expenses:
Electric production fuel and purchased power	191	138	359	271
Electric transmission service	133	121	271	255
Cost of gas sold	48	31	216	131
Other operation and maintenance	166	160	320	306
Depreciation and amortization	166	165	332	329
Taxes other than income taxes	27	26	54	52
Total operating expenses	731	641	1,552	1,344
Operating income	212	176	460	374
Other (income) and deductions:
Interest expense	78	69	152	138
Equity income from unconsolidated investments, net	(16)	(19)	(32)	(34)
Allowance for funds used during construction	(13)	(5)	(24)	(9)
Other	0	2	1	4
Total other (income) and deductions	49	47	97	99
Income before income taxes	163	129	363	275
Income tax expense (benefit)	4	(17)	12	(45)
Net income	159	146	351	320
Preferred dividend requirements of Interstate Power and Light Company	0	2	0	5
Net income attributable to common shareowners	$ 159	$ 144	$ 351	$ 315
Weighted average number of common shares outstanding:
Basic (in shares)	250,900	250,200	250,700	250,100
Diluted (in shares)	251,100	250,600	251,000	250,500
Earnings per weighted average common share attributable to Alliant Energy common shareowners:
Basic (in dollars per share)	$ 0.63	$ 0.58	$ 1.40	$ 1.26
Diluted (in dollars per share)	$ 0.63	$ 0.57	$ 1.40	$ 1.26
IPL [Member]
Revenues:
Electric utility	$ 442	$ 402	$ 843	$ 788
Gas utility	52	43	191	134
Other utility	12	10	22	22
Total revenues	506	455	1,056	944
Operating expenses:
Electric production fuel and purchased power	83	55	150	114
Electric transmission service	91	79	188	171
Cost of gas sold	27	22	112	72
Other operation and maintenance	87	81	171	158
Depreciation and amortization	95	93	189	187
Taxes other than income taxes	14	14	28	28
Total operating expenses	397	344	838	730
Operating income	109	111	218	214
Other (income) and deductions:
Interest expense	37	34	74	69
Allowance for funds used during construction	(3)	(3)	(5)	(5)
Other	0	2	(1)	2
Total other (income) and deductions	34	33	68	66
Income before income taxes	75	78	150	148
Income tax expense (benefit)	(12)	(10)	(23)	(22)
Net income	87	88	173	170
Preferred dividend requirements of Interstate Power and Light Company	0	2	0	5
Net income attributable to common shareowners	87	86	173	165
WPL [Member]
Revenues:
Electric utility	370	315	743	630
Gas utility	42	26	165	105
Other utility	1	0	1	1
Total revenues	413	341	909	736
Operating expenses:
Electric production fuel and purchased power	108	84	209	158
Electric transmission service	41	42	83	84
Cost of gas sold	21	9	104	59
Other operation and maintenance	67	69	123	128
Depreciation and amortization	69	70	139	139
Taxes other than income taxes	12	12	24	23
Total operating expenses	318	286	682	591
Operating income	95	55	227	145
Other (income) and deductions:
Interest expense	28	26	55	52
Allowance for funds used during construction	(10)	(2)	(18)	(4)
Other	0	0	0	1
Total other (income) and deductions	18	24	37	49
Income before income taxes	77	31	190	96
Income tax expense (benefit)	14	(7)	34	(26)
Net income	$ 63	$ 38	$ 156	$ 122