Reportable Segments (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Segment Reporting Information [Line Items]
Operating Revenue	$ 2,024	$ 1,725	$ 6,318	$ 5,296
Net income (loss) available to common stockholders	163	186	659	711
Plant, property, and equipment, gross	30,125		30,125		$ 29,893
Total assets	30,372		30,372		28,753
Consumers Energy Company
Segment Reporting Information [Line Items]
Operating Revenue	1,886	1,644	5,971	5,074
Net income (loss) available to common stockholders	189	186	744	711
Plant, property, and equipment, gross	28,978		28,978		28,771
Total assets	28,992		28,992		27,140
Other reconciling items
Segment Reporting Information [Line Items]
Net income (loss) available to common stockholders	(29)	(7)	(107)	(27)
Plant, property, and equipment, gross	26		26		23
Total assets	77		77		431
Other reconciling items | Consumers Energy Company
Segment Reporting Information [Line Items]
Net income (loss) available to common stockholders	8	0	4	(1)
Plant, property, and equipment, gross	25		25		23
Total assets	24		24		21
Electric Utility | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue	1,594	1,419	4,160	3,713
Net income (loss) available to common stockholders	194	195	501	504
Plant, property, and equipment, gross	17,720		17,720		18,147
Total assets	17,362		17,362		16,493
Electric Utility | Operating Segments | Consumers Energy Company
Segment Reporting Information [Line Items]
Operating Revenue	1,594	1,419	4,160	3,713
Net income (loss) available to common stockholders	194	195	501	504
Plant, property, and equipment, gross	17,720		17,720		18,147
Total assets	17,423		17,423		16,555
Gas Utility | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue	292	225	1,811	1,361
Net income (loss) available to common stockholders	(13)	(9)	239	208
Plant, property, and equipment, gross	11,233		11,233		10,601
Total assets	11,499		11,499		10,517
Gas Utility | Operating Segments | Consumers Energy Company
Segment Reporting Information [Line Items]
Operating Revenue	292	225	1,811	1,361
Net income (loss) available to common stockholders	(13)	(9)	239	208
Plant, property, and equipment, gross	11,233		11,233		10,601
Total assets	11,545		11,545		10,564
NorthStar Clean Energy | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue	138	81	347	222
Net income (loss) available to common stockholders	11	$ 7	26	$ 26
Plant, property, and equipment, gross	1,146		1,146		1,122
Total assets	$ 1,434		$ 1,434		$ 1,312