Revenue (Disaggregation of Revenue) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	$ 1,955	$ 1,671	$ 6,115	$ 5,148
Leasing income	68	50	192	136
Financing income	4	3	13	11
Consumers alternative-revenue programs			(2)	1
Total operating revenue	2,024	1,725	6,318	5,296
Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	1,591	1,416	4,151	3,705
Financing income	3	2	8	7
Consumers alternative-revenue programs			1	1
Total operating revenue	1,594	1,419	4,160	3,713
Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	294	224	1,809	1,357
Financing income	1	1	5	4
Consumers alternative-revenue programs			(3)	0
Total operating revenue	292	225	1,811	1,361
NorthStar Clean Energy | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	70	31	155	86
Leasing income	68	50	192	136
Total operating revenue	138	81	347	222
Variable lease income	57	35	154	94
Consumers Energy Company
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	1,885	1,640	5,960	5,062
Financing income	4	3	13	11
Consumers alternative-revenue programs	(3)	1	(2)	1
Total operating revenue	1,886	1,644	5,971	5,074
Consumers Energy Company | Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	1,591	1,416	4,151	3,705
Financing income	3	2	8	7
Consumers alternative-revenue programs	0	1	1	1
Total operating revenue	1,594	1,419	4,160	3,713
Consumers Energy Company | Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	294	224	1,809	1,357
Financing income	1	1	5	4
Consumers alternative-revenue programs	(3)	0	(3)	0
Total operating revenue	292	225	1,811	1,361
Residential | Consumers Energy Company
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	957	861	3,194	2,764
Residential | Consumers Energy Company | Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	767	718	1,955	1,847
Residential | Consumers Energy Company | Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	190	143	1,239	917
Commercial | Consumers Energy Company
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	566	492	1,690	1,449
Commercial | Consumers Energy Company | Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	515	456	1,319	1,191
Commercial | Consumers Energy Company | Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	51	36	371	258
Industrial | Consumers Energy Company
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	236	172	654	494
Industrial | Consumers Energy Company | Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	226	167	601	458
Industrial | Consumers Energy Company | Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	10	5	53	36
Other
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	70	31	155	86
Other | NorthStar Clean Energy | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	70	31	155	86
Other | Consumers Energy Company
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	126	115	422	355
Other | Consumers Energy Company | Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	83	75	276	209
Other | Consumers Energy Company | Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	$ 43	$ 40	$ 146	$ 146