Reportable Segments (Schedule of Financial Information by Reportable Segments, CMS Energy, including Consumers) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Segment Reporting Information [Line Items]
Operating Revenue	$ 2,021	$ 1,743	$ 6,306	$ 5,526
Power supply cost	687	560	1,905	1,527
Maintenance and other operating expenses	416	412	1,218	1,218
Depreciation and amortization	288	273	964	914
General taxes	107	99	378	356
Total operating expenses	1,540	1,376	5,014	4,464
Operating Income	481	367	1,292	1,062
Total other income	62	84	249	283
Total interest charges	203	178	588	528
Income (Loss) Before Income Taxes	340	273	953	817
Income tax expense (benefit)	68	26	193	125
Income from continuing operations	272	247	760	692
Other segment items	3	4	15	39
Net Income (Loss) Available to Common Stockholders	275	251	775	731
Plant, property, and equipment, gross	36,583	34,156	36,583	34,156	$ 34,932
Total assets	38,008	34,817	38,008	34,817	$ 35,920
Cost of gas sold
Segment Reporting Information [Line Items]
Cost of gas sold	42	32	549	449
Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue	2,021	1,743	6,306	5,526
Power supply cost	687	560	1,905	1,527
Maintenance and other operating expenses	413	408	1,210	1,209
Depreciation and amortization	288	273	964	913
General taxes	107	99	378	356
Total operating expenses	1,537	1,372	5,006	4,454
Operating Income	484	371	1,300	1,072
Total other income	60	63	168	186
Total interest charges	144	133	413	388
Income (Loss) Before Income Taxes	400	301	1,055	870
Income tax expense (benefit)	68	17	207	128
Income from continuing operations	332	284	848	742
Other segment items	5	6	22	46
Net Income (Loss) Available to Common Stockholders	337	290	870	788
Plant, property, and equipment, gross	36,553	34,135	36,553	34,135
Total assets	37,866	34,742	37,866	34,742
Operating Segments | Cost of gas sold
Segment Reporting Information [Line Items]
Cost of gas sold	42	32	549	449
Other Reconciling Items
Segment Reporting Information [Line Items]
Operating Revenue	0	0	0	0
Power supply cost	0	0	0	0
Maintenance and other operating expenses	3	4	8	9
Depreciation and amortization	0	0	0	1
General taxes	0	0	0	0
Total operating expenses	3	4	8	10
Operating Income	(3)	(4)	(8)	(10)
Total other income	2	21	81	97
Total interest charges	59	45	175	140
Income (Loss) Before Income Taxes	(60)	(28)	(102)	(53)
Income tax expense (benefit)	0	9	(14)	(3)
Income from continuing operations	(60)	(37)	(88)	(50)
Other segment items	(2)	(2)	(7)	(7)
Net Income (Loss) Available to Common Stockholders	(62)	(39)	(95)	(57)
Plant, property, and equipment, gross	30	21	30	21
Total assets	142	75	142	75
Other Reconciling Items | Cost of gas sold
Segment Reporting Information [Line Items]
Cost of gas sold	0	0	0	0
Electric Utility | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue	1,679	1,448	4,337	3,806
Power supply cost	624	515	1,707	1,408
Maintenance and other operating expenses	285	282	806	781
Depreciation and amortization	239	229	682	651
General taxes	81	75	227	214
Total operating expenses	1,229	1,101	3,422	3,054
Operating Income	450	347	915	752
Total other income	34	35	97	105
Total interest charges	92	82	263	242
Income (Loss) Before Income Taxes	392	300	749	615
Income tax expense (benefit)	66	27	131	74
Income from continuing operations	326	273	618	541
Other segment items	0	0	(1)	(1)
Net Income (Loss) Available to Common Stockholders	326	273	617	540
Plant, property, and equipment, gross	21,095	19,826	21,095	19,826
Total assets	21,917	20,222	21,917	20,222
Electric Utility | Operating Segments | Cost of gas sold
Segment Reporting Information [Line Items]
Cost of gas sold	0	0	0	0
Gas Utility | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue	234	213	1,670	1,485
Power supply cost	0	0	0	0
Maintenance and other operating expenses	103	99	331	355
Depreciation and amortization	35	32	243	226
General taxes	23	20	142	132
Total operating expenses	201	182	1,261	1,160
Operating Income	33	31	409	325
Total other income	22	25	64	70
Total interest charges	53	49	152	143
Income (Loss) Before Income Taxes	2	7	321	252
Income tax expense (benefit)	2	(4)	83	57
Income from continuing operations	0	11	238	195
Other segment items	0	0	0	0
Net Income (Loss) Available to Common Stockholders	0	11	238	195
Plant, property, and equipment, gross	13,890	12,840	13,890	12,840
Total assets	13,720	12,809	13,720	12,809
Gas Utility | Operating Segments | Cost of gas sold
Segment Reporting Information [Line Items]
Cost of gas sold	40	31	545	447
NorthStar Clean Energy | Operating Segments
Segment Reporting Information [Line Items]
Operating Revenue	108	82	299	235
Power supply cost	63	45	198	119
Maintenance and other operating expenses	25	27	73	73
Depreciation and amortization	14	12	39	36
General taxes	3	4	9	10
Total operating expenses	107	89	323	240
Operating Income	1	(7)	(24)	(5)
Total other income	4	3	7	11
Total interest charges	(1)	2	(2)	3
Income (Loss) Before Income Taxes	6	(6)	(15)	3
Income tax expense (benefit)	0	(6)	(7)	(3)
Income from continuing operations	6	0	(8)	6
Other segment items	5	6	23	47
Net Income (Loss) Available to Common Stockholders	11	6	15	53
Plant, property, and equipment, gross	1,568	1,469	1,568	1,469
Total assets	2,229	1,711	2,229	1,711
NorthStar Clean Energy | Operating Segments | Cost of gas sold
Segment Reporting Information [Line Items]
Cost of gas sold	$ 2	$ 1	$ 4	$ 2