Reportable Segments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Segment Reporting Information [Line Items]
Operating Revenue	$ 1,920	$ 1,558	$ 4,294	$ 3,571
Net income (loss) available to common stockholders	145	176	496	525
Plant, property, and equipment, gross	29,426		29,426		$ 29,893
Total assets	29,040		29,040		28,753
Consumers Energy Company
Segment Reporting Information [Line Items]
Operating Revenue	1,802	1,493	4,085	3,430
Net income (loss) available to common stockholders	172	189	555	525
Plant, property, and equipment, gross	28,304		28,304		28,771
Total assets	27,715		27,715		27,140
Other reconciling items
Segment Reporting Information [Line Items]
Net income (loss) available to common stockholders	(38)	(19)	(78)	(20)
Plant, property, and equipment, gross	25		25		23
Total assets	68		68		431
Other reconciling items | Consumers Energy Company
Segment Reporting Information [Line Items]
Net income (loss) available to common stockholders	(4)	(1)	(4)	(1)
Plant, property, and equipment, gross	25		25		23
Total assets	22		22		21
Electric Utility | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue	1,325	1,160	2,566	2,294
Net income (loss) available to common stockholders	140	154	307	309
Plant, property, and equipment, gross	17,333		17,333		18,147
Total assets	16,860		16,860		16,493
Electric Utility | Operating Segments | Consumers Energy Company
Segment Reporting Information [Line Items]
Operating Revenue	1,325	1,160	2,566	2,294
Net income (loss) available to common stockholders	140	154	307	309
Plant, property, and equipment, gross	17,333		17,333		18,147
Total assets	16,922		16,922		16,555
Gas Utility | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue	477	333	1,519	1,136
Net income (loss) available to common stockholders	36	36	252	217
Plant, property, and equipment, gross	10,946		10,946		10,601
Total assets	10,725		10,725		10,517
Gas Utility | Operating Segments | Consumers Energy Company
Segment Reporting Information [Line Items]
Operating Revenue	477	333	1,519	1,136
Net income (loss) available to common stockholders	36	36	252	217
Plant, property, and equipment, gross	10,946		10,946		10,601
Total assets	10,771		10,771		10,564
Enterprises | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue	118	65	209	141
Net income (loss) available to common stockholders	7	$ 5	15	$ 19
Plant, property, and equipment, gross	1,122		1,122		1,122
Total assets	$ 1,387		$ 1,387		$ 1,312