Revenue (Disaggregation of Revenue) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	$ 7,320	$ 7,261	$ 8,320
Leasing income	105	116	240
Financing income	15	16	16
Alternative-revenue programs			57
Revenues to be refunded			(37)
Total operating revenue	7,515	7,462	8,596
Operating Segments
Disaggregation of Revenue [Line Items]
Total operating revenue	7,515	7,462	8,596
Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	4,995	4,686	5,395
Financing income	10	10	10
Alternative-revenue programs			43
Revenues to be refunded			(29)
Total operating revenue	5,061	4,745	5,419
Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	2,114	2,394	2,720
Financing income	5	6	6
Alternative-revenue programs			14
Revenues to be refunded			(8)
Total operating revenue	2,138	2,420	2,732
NorthStar Clean Energy | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	211	181	205
Leasing income	105	116	240
Total operating revenue	316	297	445
Consumers Energy Company
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	7,109	7,080	8,115
Financing income	15	16	16
Alternative-revenue programs	75	69	57
Other non-segment revenue	1	1
Revenues to be refunded			(37)
Total operating revenue	7,200	7,166	8,151
Consumers Energy Company | Operating Segments
Disaggregation of Revenue [Line Items]
Total operating revenue	7,199	7,165	8,151
Consumers Energy Company | Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	4,995	4,686	5,395
Financing income	10	10	10
Alternative-revenue programs	56	49	43
Revenues to be refunded			(29)
Total operating revenue	5,061	4,745	5,419
Consumers Energy Company | Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	2,114	2,394	2,720
Financing income	5	6	6
Alternative-revenue programs	19	20	14
Revenues to be refunded			(8)
Total operating revenue	2,138	2,420	2,732
Residential | Consumers Energy Company
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	3,747	3,855	4,402
Residential | Consumers Energy Company | Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	2,318	2,236	2,523
Residential | Consumers Energy Company | Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	1,429	1,619	1,879
Commercial | Consumers Energy Company
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	2,114	2,039	2,292
Commercial | Consumers Energy Company | Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	1,674	1,550	1,733
Commercial | Consumers Energy Company | Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	440	489	559
Industrial | Consumers Energy Company
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	720	720	867
Industrial | Consumers Energy Company | Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	670	660	792
Industrial | Consumers Energy Company | Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	50	60	75
Other
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	211	181	205
Other | NorthStar Clean Energy | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	211	181	205
Other | Consumers Energy Company
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	528	466	554
Other | Consumers Energy Company | Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	333	240	347
Other | Consumers Energy Company | Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	$ 195	$ 226	$ 207