Consolidated Statements of Income (USD $) In Millions, except Per Share data	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Operating Revenue	$ 1,464	$ 1,443	$ 4,883	$ 4,750
Operating Expenses
Fuel for electric generation	199	183	504	472
Purchased and interchange power	365	363	968	955
Purchased power - related parties	23	21	64	63
Cost of gas sold	107	104	1,095	1,060
Maintenance and other operating expenses	301	273	868	844
Depreciation and amortization	120	133	404	436
General taxes	33	49	151	156
Insurance settlement	0	0	0	(50)
Gain on asset sales, net	0	(2)	0	(6)
Total operating expenses	1,148	1,124	4,054	3,930
Operating Income	316	319	829	820
Other Income (Expense)
Interest income	4	5	8	14
Allowance for equity funds used during construction	1	1	4	4
Income from equity method investees	4	3	10	8
Other income	3	9	12	27
Other expense	(3)	(2)	(8)	(7)
Total other income	9	16	26	46
Interest Charges
Interest on long-term debt	99	97	298	293
Other interest expense	6	6	18	34
Allowance for borrowed funds used during construction	(1)	(1)	(3)	(3)
Total interest charges	104	102	313	324
Income Before Income Taxes	221	233	542	542
Income Tax Expense	81	87	168	207
Income from Continuing Operations	140	146	374	335
Income (Loss) From Discontinued Operations, Net of Tax	0	0	2	(17)
Net Income	140	146	376	318
Income Attributable to Noncontrolling Interests	1	1	2	3
Net Income Attributable to CMS Energy	139	145	374	315
Charge for Deferred Issuance Costs on Preferred Stock	0	8	0	8
Preferred Stock Dividends	0	3	0	8
Net Income Available to Common Stockholders	139	134	374	299
Net Income Attributable to Common Stockholders
Amounts Attributable to Continuing Operations	139	134	372	316
Amounts Attributable to Discontinued Operations	0	0	2	(17)
Net Income Available to Common Stockholders	139	134	374	299
Income Attributable to Noncontrolling Interests
Amounts Attributable to Continuing Operations	1	1	2	3
Loss from Discontinued Operations	0	0	0	0
Income Attributable to Noncontrolling Interests	1	1	2	3
Basic Earnings Per Average Common Share
Basic Earnings from Continuing Operations	$ 0.55	$ 0.58	$ 1.48	$ 1.38
Basic Earnings (Loss) from Discontinued Operations	$ 0.00	$ 0.00	$ 0.01	$ (0.08)
Basic Earnings Attributable to Common Stock	$ 0.55	$ 0.58	$ 1.49	$ 1.30
Diluted Earnings Per Average Common Share
Diluted Earnings from Continuing Operations	$ 0.53	$ 0.53	$ 1.42	$ 1.26
Diluted Earnings (Loss) from Discontinued Operations	$ 0.00	$ 0.00	$ 0.01	$ (0.07)
Diluted Earnings Attributable to Common Stock	$ 0.53	$ 0.53	$ 1.43	$ 1.19
Dividends Declared Per Common Share	$ 0.21	$ 0.15	$ 0.63	$ 0.45
Consumers Energy Company [Member]
Operating Revenue	1,397	1,370	4,688	4,536
Operating Expenses
Fuel for electric generation	175	157	442	407
Purchased and interchange power	362	359	954	946
Purchased power - related parties	24	22	64	63
Cost of gas sold	88	92	1,038	1,001
Maintenance and other operating expenses	286	258	824	801
Depreciation and amortization	119	131	401	432
General taxes	38	47	153	151
Total operating expenses	1,092	1,066	3,876	3,801
Operating Income	305	304	812	735
Other Income (Expense)
Interest income	2	4	6	13
Interest and dividend income - related parties	1		1
Allowance for equity funds used during construction	1	1	4	4
Other income	3	9	16	27
Other expense	(3)	(2)	(8)	(7)
Total other income	4	12	19	37
Interest Charges
Interest on long-term debt	62	60	188	183
Other interest expense	5	5	14	30
Allowance for borrowed funds used during construction	(1)	(1)	(3)	(3)
Total interest charges	66	64	199	210
Income Before Income Taxes	243	252	632	562
Income Tax Expense	88	92	232	207
Net Income	155	160	400	355
Preferred Stock Dividends	1	1	2	2
Net Income Available to Common Stockholders	154	159	398	353
Net Income Attributable to Common Stockholders
Net Income Available to Common Stockholders	$ 154	$ 159	$ 398	$ 353