Consolidated Statements of Income (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Operating Revenue	$ 1,333	$ 1,364	$ 3,076	$ 3,419
Operating Expenses
Fuel for electric generation	126	153	256	305
Purchased and interchange power	334	303	651	603
Purchased power - related parties	20	20	42	41
Cost of gas sold	133	220	683	988
Maintenance and other operating expenses	282	288	577	567
Depreciation and amortization	130	122	302	284
General taxes	48	51	117	118
Total operating expenses	1,073	1,157	2,628	2,906
Operating Income	260	207	448	513
Other Income (Expense)
Interest income	1	2	2	4
Allowance for equity funds used during construction	2	2	4	3
Income (loss) from equity method investees	3	2	8	6
Other income	3	5	6	9
Other expense	(3)	(3)	(5)	(5)
Total other income	6	8	15	17
Interest Charges
Interest on long-term debt	94	99	188	199
Other interest expense	5	6	11	12
Allowance for borrowed funds used during construction	(1)	(1)	(2)	(2)
Total interest charges	98	104	197	209
Income Before Income Taxes	168	111	266	321
Income Tax Expense	67	10	105	87
Income from Continuing Operations	101	101	161	234
Income From Discontinued Operations, Net of Tax			7	2
Net Income	101	101	168	236
Income Attributable to Noncontrolling Interests	1	1	1	1
Net income available to common stockholders	100	100	167	235
Net Income Attributable to Common Stockholders
Amounts attributable to continuing operations	100	100	160	233
Amounts attributable to discontinued operations		0	7	2
Net income available to common stockholders	100	100	167	235
Income Attributable to Noncontrolling Interests
Amounts Attributable to Continuing Operations	1	1	1	1
Loss from Discontinued Operations		0		0
Income Attributable to Noncontrolling Interests	1	1	1	1
Basic Earnings Per Average Common Share
Basic earnings from continuing operations	$ 0.38	$ 0.40	$ 0.61	$ 0.93
Basic earnings from discontinued operations		$ 0.00	$ 0.03	$ 0.01
Basic earnings attributable to common stock	$ 0.38	$ 0.40	$ 0.64	$ 0.94
Diluted Earnings Per Average Common Share
Diluted earnings from continuing operations	$ 0.37	$ 0.38	$ 0.59	$ 0.89
Diluted earnings from discontinued operations		$ 0.00	$ 0.03	$ 0.01
Diluted earnings attributable to common stock	$ 0.37	$ 0.38	$ 0.62	$ 0.90
Dividends Declared Per Common Share	$ 0.24	$ 0.21	$ 0.48	$ 0.42
Consumers Energy Company [Member]
Operating Revenue	1,282	1,303	2,957	3,291
Operating Expenses
Fuel for electric generation	110	138	216	267
Purchased and interchange power	327	299	640	592
Purchased power - related parties	21	19	42	40
Cost of gas sold	124	197	660	950
Maintenance and other operating expenses	266	273	543	538
Depreciation and amortization	128	121	299	282
General taxes	46	49	114	115
Total operating expenses	1,022	1,096	2,514	2,784
Operating Income	260	207	443	507
Other Income (Expense)
Interest income	1	2	2	4
Allowance for equity funds used during construction	2	2	4	3
Other income	3	5	11	13
Other expense	(3)	(3)	(5)	(5)
Total other income	3	6	12	15
Interest Charges
Interest on long-term debt	58	63	119	126
Other interest expense	4	5	8	9
Allowance for borrowed funds used during construction	(1)	(1)	(2)	(2)
Total interest charges	61	67	125	133
Income Before Income Taxes	202	146	330	389
Income Tax Expense	80	54	132	144
Net Income	122	92	198	245
Preferred Stock Dividends	1	1	1	1
Net income available to common stockholders	121	91	197	244
Net Income Attributable to Common Stockholders
Net income available to common stockholders	$ 121	$ 91	$ 197	$ 244