Revenue (Disaggregation of Revenue) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	$ 1,711	$ 1,639	$ 5,431	$ 5,401
Leasing income	26	30	77	88
Financing income	5	3	13	12
Total operating revenue	1,743	1,673	5,526	5,512
Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	1,443	1,348	3,793	3,552
Financing income	4	2	8	7
Total operating revenue	1,448	1,351	3,806	3,570
Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	212	243	1,480	1,715
Financing income	1	1	5	5
Total operating revenue	213	244	1,485	1,720
NorthStar Clean Energy | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	56	48	158	134
Leasing income	26	30	77	88
Total operating revenue	82	78	235	222
Variable lease income	15	19	44	57
Consumers Energy Company
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	1,655	1,591	5,273	5,267
Financing income	5	3	13	12
Alternative-revenue programs	1	1	5	11
Other non-segment revenue		1		1
Total operating revenue	1,661	1,596	5,291	5,291
Consumers Energy Company | Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	1,443	1,348	3,793	3,552
Financing income	4	2	8	7
Alternative-revenue programs	1	1	5	11
Total operating revenue	1,448	1,351	3,806	3,570
Consumers Energy Company | Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	212	243	1,480	1,715
Financing income	1	1	5	5
Alternative-revenue programs	0	0	0	0
Total operating revenue	213	244	1,485	1,720
Residential | Consumers Energy Company
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	834	821	2,777	2,867
Residential | Consumers Energy Company | Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	707	666	1,779	1,707
Residential | Consumers Energy Company | Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	127	155	998	1,160
Commercial | Consumers Energy Company
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	526	481	1,590	1,536
Commercial | Consumers Energy Company | Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	486	443	1,279	1,183
Commercial | Consumers Energy Company | Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	40	38	311	353
Industrial | Consumers Energy Company
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	174	180	536	539
Industrial | Consumers Energy Company | Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	169	175	499	495
Industrial | Consumers Energy Company | Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	5	5	37	44
Other
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	56	48	158	134
Other | NorthStar Clean Energy | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	56	48	158	134
Other | Consumers Energy Company
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	121	109	370	325
Other | Consumers Energy Company | Electric Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	81	64	236	167
Other | Consumers Energy Company | Gas Utility | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue recognized from contracts with customers	$ 40	$ 45	$ 134	$ 158