Reportable Segments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Operating Revenue	$ 7,462	$ 8,596	$ 7,329
Depreciation and amortization	1,180	1,126	1,114
Income from equity method investees	7	3	10
Total interest charges	643	519	500
Income Tax Expense	147	93	95
Net income (loss) available to common stockholders	877	827	1,348
Plant, property, and equipment, gross	33,135	30,491	29,893
Investments	76	71	71
Total assets	33,517	31,353	28,753
Capital expenditures	3,280	2,393	2,161
Consumers Energy Company
Segment Reporting Information [Line Items]
Operating Revenue	7,166	8,151	7,021
Depreciation and amortization	1,137	1,088	1,077
Total interest charges	448	335	311
Income Tax Expense	161	140	156
Net income (loss) available to common stockholders	865	943	866
Plant, property, and equipment, gross	31,723	29,342	28,771
Total assets	31,852	29,916	27,140
Capital expenditures	3,145	2,280	2,144
Other reconciling items
Segment Reporting Information [Line Items]
Depreciation and amortization	2	1	1
Total interest charges	202	182	183
Income Tax Expense	(22)	(51)	(59)
Net income (loss) available to common stockholders	(55)	(152)	458
Plant, property, and equipment, gross	30	30	23
Total assets	202	109	431
Capital expenditures	2	7	2
Other reconciling items | Consumers Energy Company
Segment Reporting Information [Line Items]
Operating Revenue	1	0	0
Depreciation and amortization	2	1	1
Total interest charges	2	1	0
Income Tax Expense	(4)	(1)	0
Net income (loss) available to common stockholders	0	(2)	(1)
Plant, property, and equipment, gross	38	29	23
Total assets	38	30	21
Capital expenditures	23	7	2
Electric Utility | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue	4,745	5,419	4,958
Depreciation and amortization	797	757	772
Total interest charges	281	218	207
Income Tax Expense	67	109	117
Net income (loss) available to common stockholders	550	567	565
Plant, property, and equipment, gross	19,302	17,870	18,147
Total assets	19,358	17,907	16,493
Capital expenditures	2,081	1,265	1,153
Electric Utility | Operating Segments | Consumers Energy Company
Segment Reporting Information [Line Items]
Operating Revenue	4,745	5,419	4,958
Depreciation and amortization	797	757	772
Total interest charges	285	218	207
Income Tax Expense	67	109	117
Net income (loss) available to common stockholders	550	567	565
Plant, property, and equipment, gross	19,302	17,870	18,147
Total assets	19,417	17,968	16,555
Capital expenditures	2,081	1,265	1,153
Gas Utility | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue	2,420	2,732	2,063
Depreciation and amortization	338	330	304
Total interest charges	158	116	104
Income Tax Expense	98	32	39
Net income (loss) available to common stockholders	315	378	302
Plant, property, and equipment, gross	12,383	11,443	10,601
Total assets	12,353	11,873	10,517
Capital expenditures	1,041	1,008	989
Gas Utility | Operating Segments | Consumers Energy Company
Segment Reporting Information [Line Items]
Operating Revenue	2,420	2,732	2,063
Depreciation and amortization	338	330	304
Total interest charges	161	116	104
Income Tax Expense	98	32	39
Net income (loss) available to common stockholders	315	378	302
Plant, property, and equipment, gross	12,383	11,443	10,601
Total assets	12,397	11,918	10,564
Capital expenditures	1,041	1,008	989
NorthStar Clean Energy | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue	297	445	308
Depreciation and amortization	43	38	37
Income from equity method investees	7	3	10
Total interest charges	2	3	6
Income Tax Expense	4	3	(2)
Net income (loss) available to common stockholders	67	34	23
Plant, property, and equipment, gross	1,420	1,148	1,122
Investments	76	71	71
Total assets	1,604	1,464	1,312
Capital expenditures	$ 156	$ 113	$ 17