Reportable Segments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Segment Reporting Information [Line Items]
Operating Revenue	$ 1,555	$ 1,920	$ 3,839	$ 4,294
Net income (loss) available to common stockholders	195	145	397	496
Plant, property, and equipment, gross	31,592		31,592		$ 30,491
Total assets	32,265		32,265		31,353
Consumers Energy Company
Segment Reporting Information [Line Items]
Operating Revenue	1,485	1,802	3,695	4,085
Net income (loss) available to common stockholders	166	172	398	555
Plant, property, and equipment, gross	30,445		30,445		29,342
Total assets	30,588		30,588		29,916
Other reconciling items
Segment Reporting Information [Line Items]
Net income (loss) available to common stockholders	22	(38)	(7)	(78)
Plant, property, and equipment, gross	28		28		30
Total assets	288		288		109
Other reconciling items | Consumers Energy Company
Segment Reporting Information [Line Items]
Net income (loss) available to common stockholders	(4)	(4)	4	(4)
Plant, property, and equipment, gross	35		35		29
Total assets	42		42		30
Electric Utility | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue	1,128	1,325	2,219	2,566
Net income (loss) available to common stockholders	147	140	217	307
Plant, property, and equipment, gross	18,615		18,615		17,870
Total assets	18,889		18,889		17,907
Electric Utility | Operating Segments | Consumers Energy Company
Segment Reporting Information [Line Items]
Operating Revenue	1,128	1,325	2,219	2,566
Net income (loss) available to common stockholders	147	140	217	307
Plant, property, and equipment, gross	18,615		18,615		17,870
Total assets	18,949		18,949		17,968
Gas Utility | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue	357	477	1,476	1,519
Net income (loss) available to common stockholders	23	36	177	252
Plant, property, and equipment, gross	11,795		11,795		11,443
Total assets	11,552		11,552		11,873
Gas Utility | Operating Segments | Consumers Energy Company
Segment Reporting Information [Line Items]
Operating Revenue	357	477	1,476	1,519
Net income (loss) available to common stockholders	23	36	177	252
Plant, property, and equipment, gross	11,795		11,795		11,443
Total assets	11,597		11,597		11,918
NorthStar Clean Energy | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue	70	118	144	209
Net income (loss) available to common stockholders	3	$ 7	10	$ 15
Plant, property, and equipment, gross	1,154		1,154		1,148
Total assets	$ 1,536		$ 1,536		$ 1,464