Reportable Segments (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Segment Reporting Information [Line Items]
Operating Revenue	$ 1,673	$ 2,024	$ 5,512	$ 6,318
Net income (loss) available to common stockholders	174	163	571	659
Plant, property, and equipment, gross	31,997		31,997		$ 30,491
Total assets	32,513		32,513		31,353
Consumers Energy Company
Segment Reporting Information [Line Items]
Operating Revenue	1,596	1,886	5,291	5,971
Net income (loss) available to common stockholders	178	189	576	744
Plant, property, and equipment, gross	30,825		30,825		29,342
Total assets	30,941		30,941		29,916
Other reconciling items
Segment Reporting Information [Line Items]
Net income (loss) available to common stockholders	(33)	(29)	(40)	(107)
Plant, property, and equipment, gross	31		31		30
Total assets	148		148		109
Other reconciling items | Consumers Energy Company
Segment Reporting Information [Line Items]
Operating Revenue	1	0	1	0
Net income (loss) available to common stockholders	(13)	8	(9)	4
Plant, property, and equipment, gross	38		38		29
Total assets	47		47		30
Electric Utility | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue	1,351	1,594	3,570	4,160
Net income (loss) available to common stockholders	187	194	404	501
Plant, property, and equipment, gross	18,802		18,802		17,870
Total assets	18,856		18,856		17,907
Electric Utility | Operating Segments | Consumers Energy Company
Segment Reporting Information [Line Items]
Operating Revenue	1,351	1,594	3,570	4,160
Net income (loss) available to common stockholders	187	194	404	501
Plant, property, and equipment, gross	18,802		18,802		17,870
Total assets	18,915		18,915		17,968
Gas Utility | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue	244	292	1,720	1,811
Net income (loss) available to common stockholders	4	(13)	181	239
Plant, property, and equipment, gross	11,985		11,985		11,443
Total assets	11,934		11,934		11,873
Gas Utility | Operating Segments | Consumers Energy Company
Segment Reporting Information [Line Items]
Operating Revenue	244	292	1,720	1,811
Net income (loss) available to common stockholders	4	(13)	181	239
Plant, property, and equipment, gross	11,985		11,985		11,443
Total assets	11,979		11,979		11,918
NorthStar Clean Energy | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue	78	138	222	347
Net income (loss) available to common stockholders	16	$ 11	26	$ 26
Plant, property, and equipment, gross	1,179		1,179		1,148
Total assets	$ 1,575		$ 1,575		$ 1,464