Revenue (Disaggregation of Revenue) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	$ 2,398	$ 2,144
Leasing income	42	27
Financing income	5	4
Total operating revenue	2,447	2,176
Operating Segments
Disaggregation of Revenue [Line Items]
Total operating revenue	2,447	2,176
Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	1,294	1,129
Financing income	3	2
Total operating revenue	1,299	1,132
Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	1,047	963
Financing income	2	2
Total operating revenue	1,049	965
NorthStar Clean Energy | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	57	52
Leasing income	42	27
Total operating revenue	99	79
NorthStar Clean Energy | Operating Segments | Power Sales Agreement
Disaggregation of Revenue [Line Items]
Variable lease income	31	16
Consumers Energy Company
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	2,341	2,092
Financing income	5	4
Alternative-revenue programs	2	1
Total operating revenue	2,348	2,097
Consumers Energy Company | Operating Segments
Disaggregation of Revenue [Line Items]
Total operating revenue	2,348	2,097
Consumers Energy Company | Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	1,294	1,129
Financing income	3	2
Alternative-revenue programs	2	1
Total operating revenue	1,299	1,132
Consumers Energy Company | Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	1,047	963
Financing income	2	2
Alternative-revenue programs	0	0
Total operating revenue	1,049	965
Residential | Consumers Energy Company
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	1,325	1,190
Residential | Consumers Energy Company | Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	594	525
Residential | Consumers Energy Company | Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	731	665
Commercial | Consumers Energy Company
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	657	567
Commercial | Consumers Energy Company | Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	418	360
Commercial | Consumers Energy Company | Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	239	207
Industrial | Consumers Energy Company
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	203	180
Industrial | Consumers Energy Company | Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	173	156
Industrial | Consumers Energy Company | Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	30	24
Other
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	57	52
Other | NorthStar Clean Energy | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	57	52
Other | Consumers Energy Company
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	156	155
Other | Consumers Energy Company | Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	109	88
Other | Consumers Energy Company | Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	$ 47	$ 67