Reportable Segments (Schedule of Financial Information by Reportable Segments, CMS Energy, including Consumers) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Operating Revenue	$ 7,515	$ 7,462	$ 8,596
Power supply cost	2,028	2,011	2,909
Maintenance and other operating expenses	1,638	1,687	1,669
Depreciation and amortization	1,240	1,180	1,126
General taxes	482	447	412
Total operating expenses	6,028	6,227	7,372
Operating Income	1,487	1,235	1,224
Total other income	344	362	197
Total interest charges	708	643	519
Income (Loss) Before Income Taxes	1,123	954	902
Income tax expense (benefit)	176	147	93
Income (Loss) From Continuing Operations	947	807	809
Other segment items	46	70	18
Net Income (Loss) Available to Common Stockholders	993	877	827
Plant, property, and equipment, gross	34,932	33,135
Investments	64	74
Total assets	35,920	33,517
Capital expenditures	3,301	3,280
Income from equity method investees	7	7	3
Cost of gas sold
Segment Reporting Information [Line Items]
Cost of gas sold	640	902	1,256
Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue	7,515	7,462	8,596
Power supply cost	2,028	2,011	2,909
Maintenance and other operating expenses	1,621	1,674	1,658
Depreciation and amortization	1,239	1,178	1,125
General taxes	481	446	411
Total operating expenses	6,009	6,211	7,359
Operating Income	1,506	1,251	1,237
Total other income	226	220	199
Total interest charges	520	448	337
Income (Loss) Before Income Taxes	1,212	1,023	1,099
Income tax expense (benefit)	196	169	144
Income (Loss) From Continuing Operations	1,016	854	955
Other segment items	56	78	24
Net Income (Loss) Available to Common Stockholders	1,072	932	979
Plant, property, and equipment, gross	34,911	33,105
Investments	64	74
Total assets	35,850	33,315
Capital expenditures	3,300	3,278
Operating Segments | Cost of gas sold
Segment Reporting Information [Line Items]
Cost of gas sold	640	902	1,256
Other Reconciling Items
Segment Reporting Information [Line Items]
Operating Revenue	0	0	0
Power supply cost	0	0	0
Maintenance and other operating expenses	17	13	11
Depreciation and amortization	1	2	1
General taxes	1	1	1
Total operating expenses	19	16	13
Operating Income	(19)	(16)	(13)
Total other income	118	142	(2)
Total interest charges	188	195	182
Income (Loss) Before Income Taxes	(89)	(69)	(197)
Income tax expense (benefit)	(20)	(22)	(51)
Income (Loss) From Continuing Operations	(69)	(47)	(146)
Other segment items	(10)	(8)	(6)
Net Income (Loss) Available to Common Stockholders	(79)	(55)	(152)
Plant, property, and equipment, gross	21	30
Investments	0	0
Total assets	70	202
Capital expenditures	1	2
Other Reconciling Items | Cost of gas sold
Segment Reporting Information [Line Items]
Cost of gas sold	0	0	0
Electric Utility | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue	5,061	4,745	5,419
Power supply cost	1,867	1,841	2,605
Maintenance and other operating expenses	1,066	1,075	1,028
Depreciation and amortization	865	797	757
General taxes	281	260	240
Total operating expenses	4,079	3,973	4,630
Operating Income	982	772	789
Total other income	126	131	106
Total interest charges	324	285	218
Income (Loss) Before Income Taxes	784	618	677
Income tax expense (benefit)	102	67	109
Income (Loss) From Continuing Operations	682	551	568
Other segment items	(1)	(1)	(1)
Net Income (Loss) Available to Common Stockholders	681	550	567
Plant, property, and equipment, gross	20,137	19,302
Investments	0	0
Total assets	20,710	19,358
Capital expenditures	1,871	2,081
Electric Utility | Operating Segments | Cost of gas sold
Segment Reporting Information [Line Items]
Cost of gas sold	0	0	0
Gas Utility | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue	2,138	2,420	2,732
Power supply cost	0	0	0
Maintenance and other operating expenses	454	511	554
Depreciation and amortization	325	338	330
General taxes	188	176	159
Total operating expenses	1,604	1,922	2,286
Operating Income	534	498	446
Total other income	86	77	81
Total interest charges	192	161	116
Income (Loss) Before Income Taxes	428	414	411
Income tax expense (benefit)	99	98	32
Income (Loss) From Continuing Operations	329	316	379
Other segment items	(1)	(1)	(1)
Net Income (Loss) Available to Common Stockholders	328	315	378
Plant, property, and equipment, gross	13,268	12,383
Investments	0	0
Total assets	13,247	12,353
Capital expenditures	1,141	1,041
Gas Utility | Operating Segments | Cost of gas sold
Segment Reporting Information [Line Items]
Cost of gas sold	637	897	1,243
NorthStar Clean Energy | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue	316	297	445
Power supply cost	161	170	304
Maintenance and other operating expenses	101	88	76
Depreciation and amortization	49	43	38
General taxes	12	10	12
Total operating expenses	326	316	443
Operating Income	(10)	(19)	2
Total other income	14	12	12
Total interest charges	4	2	3
Income (Loss) Before Income Taxes	0	(9)	11
Income tax expense (benefit)	(5)	4	3
Income (Loss) From Continuing Operations	5	(13)	8
Other segment items	58	80	26
Net Income (Loss) Available to Common Stockholders	63	67	34
Plant, property, and equipment, gross	1,506	1,420
Investments	64	74
Total assets	1,893	1,604
Capital expenditures	288	156
NorthStar Clean Energy | Operating Segments | Cost of gas sold
Segment Reporting Information [Line Items]
Cost of gas sold	$ 3	$ 5	$ 13