Consolidated Statements of Comprehensive Income (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
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
Retirement benefits liability adjustments	1	1	2	1
Unrealized gain (loss) on investments, net of tax	1	1	2	1
Other Comprehensive Income	2	2	4	2
Total Comprehensive Income	102	102	171	237
Consumers Energy Company [Member]
Net income	122	92	198	245
Net income available to common stockholders	121	91	197	244
Retirement benefits liability adjustments			1	1
Unrealized gain (loss) on investments, net of tax	3			(1)
Other Comprehensive Income	3	0	1	0
Total Comprehensive Income	$ 125	$ 92	$ 199	$ 245