Reportable Segments (Schedule of Financial Information by Reportable Segments, CMS Energy, including Consumers) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024
Segment Reporting Information [Line Items]
Operating Revenue	$ 2,447	$ 2,176
Power supply cost	615	488
Maintenance and other operating expenses	405	402
Depreciation and amortization	388	368
General taxes	162	155
Total operating expenses	1,953	1,764
Operating Income	494	412
Total other income	50	86
Total interest charges	186	177
Income (Loss) Before Income Taxes	358	321
Income tax expense (benefit)	63	58
Income (Loss) From Continuing Operations	295	263
Other segment items	7	22
Net Income (Loss) Available to Common Stockholders	302	285
Plant, property, and equipment, gross	35,281	33,236	$ 34,932
Total assets	36,295	33,901	$ 35,920
Cost of gas sold
Segment Reporting Information [Line Items]
Cost of gas sold	383	351
Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue	2,447	2,176
Power supply cost	615	488
Maintenance and other operating expenses	403	400
Depreciation and amortization	388	367
General taxes	162	155
Total operating expenses	1,951	1,761
Operating Income	496	415
Total other income	47	62
Total interest charges	130	130
Income (Loss) Before Income Taxes	413	347
Income tax expense (benefit)	103	74
Income (Loss) From Continuing Operations	310	273
Other segment items	9	24
Net Income (Loss) Available to Common Stockholders	319	297
Plant, property, and equipment, gross	35,257	33,216
Total assets	35,877	33,679
Operating Segments | Cost of gas sold
Segment Reporting Information [Line Items]
Cost of gas sold	383	351
Other Reconciling Items
Segment Reporting Information [Line Items]
Operating Revenue	0	0
Power supply cost	0	0
Maintenance and other operating expenses	2	2
Depreciation and amortization	0	1
General taxes	0	0
Total operating expenses	2	3
Operating Income	(2)	(3)
Total other income	3	24
Total interest charges	56	47
Income (Loss) Before Income Taxes	(55)	(26)
Income tax expense (benefit)	(40)	(16)
Income (Loss) From Continuing Operations	(15)	(10)
Other segment items	(2)	(2)
Net Income (Loss) Available to Common Stockholders	(17)	(12)
Plant, property, and equipment, gross	24	20
Total assets	418	222
Other Reconciling Items | Cost of gas sold
Segment Reporting Information [Line Items]
Cost of gas sold	0	0
Electric Utility | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue	1,299	1,132
Power supply cost	546	449
Maintenance and other operating expenses	257	238
Depreciation and amortization	221	213
General taxes	73	71
Total operating expenses	1,097	971
Operating Income	202	161
Total other income	27	34
Total interest charges	82	81
Income (Loss) Before Income Taxes	147	114
Income tax expense (benefit)	23	17
Income (Loss) From Continuing Operations	124	97
Other segment items	0	0
Net Income (Loss) Available to Common Stockholders	124	97
Plant, property, and equipment, gross	20,340	19,317
Total assets	20,875	19,759
Electric Utility | Operating Segments | Cost of gas sold
Segment Reporting Information [Line Items]
Cost of gas sold	0	0
Gas Utility | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue	1,049	965
Power supply cost	0	0
Maintenance and other operating expenses	116	140
Depreciation and amortization	154	143
General taxes	86	81
Total operating expenses	738	714
Operating Income	311	251
Total other income	19	22
Total interest charges	48	48
Income (Loss) Before Income Taxes	282	225
Income tax expense (benefit)	69	56
Income (Loss) From Continuing Operations	213	169
Other segment items	0	0
Net Income (Loss) Available to Common Stockholders	213	169
Plant, property, and equipment, gross	13,412	12,475
Total assets	13,025	12,305
Gas Utility | Operating Segments | Cost of gas sold
Segment Reporting Information [Line Items]
Cost of gas sold	382	350
NorthStar Clean Energy | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue	99	79
Power supply cost	69	39
Maintenance and other operating expenses	30	22
Depreciation and amortization	13	11
General taxes	3	3
Total operating expenses	116	76
Operating Income	(17)	3
Total other income	1	6
Total interest charges	0	1
Income (Loss) Before Income Taxes	(16)	8
Income tax expense (benefit)	11	1
Income (Loss) From Continuing Operations	(27)	7
Other segment items	9	24
Net Income (Loss) Available to Common Stockholders	(18)	31
Plant, property, and equipment, gross	1,505	1,424
Total assets	1,977	1,615
NorthStar Clean Energy | Operating Segments | Cost of gas sold
Segment Reporting Information [Line Items]
Cost of gas sold	$ 1	$ 1