Revenue (Disaggregation of Revenue) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	$ 2,248	$ 2,318
Leasing income	31	58
Financing income	5	5
Consumers alternative-revenue programs		(7)
Total operating revenue	2,284	2,374
Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	1,089	1,238
Financing income	2	3
Consumers alternative-revenue programs		0
Total operating revenue	1,091	1,241
Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	1,116	1,047
Financing income	3	2
Consumers alternative-revenue programs		(7)
Total operating revenue	1,119	1,042
NorthStar Clean Energy | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	43	33
Leasing income	31	58
Total operating revenue	74	91
Variable lease income	22	44
Consumers Energy Company
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	2,205	2,285
Financing income	5	5
Consumers alternative-revenue programs		(7)
Total operating revenue	2,210	2,283
Consumers Energy Company | Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	1,089	1,238
Financing income	2	3
Consumers alternative-revenue programs		0
Total operating revenue	1,091	1,241
Consumers Energy Company | Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	1,116	1,047
Financing income	3	2
Consumers alternative-revenue programs		(7)
Total operating revenue	1,119	1,042
Residential | Consumers Energy Company
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	1,304	1,331
Residential | Consumers Energy Company | Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	528	591
Residential | Consumers Energy Company | Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	776	740
Commercial | Consumers Energy Company
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	594	605
Commercial | Consumers Energy Company | Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	347	384
Commercial | Consumers Energy Company | Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	247	221
Industrial | Consumers Energy Company
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	192	196
Industrial | Consumers Energy Company | Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	161	168
Industrial | Consumers Energy Company | Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	31	28
Other
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	43	33
Other | NorthStar Clean Energy | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	43	33
Other | Consumers Energy Company
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	115	153
Other | Consumers Energy Company | Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	53	95
Other | Consumers Energy Company | Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	$ 62	$ 58