Other Income and Other Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Fee income	$ 9	$ 8	$ 7
All other	1	3	3
Total other income	10	11	10
Civic and political expenditures	(10)	(14)	(5)
Donations	(1)	(15)	(4)
Loss on reacquired and extinguished debt		(20)	(4)
All other	(6)	(6)	(7)
Total other expense	(17)	(55)	(20)
Consumers Energy Company [Member]
Fee income	9	8	7
Gain on CMS Energy common stock	9		4
All other	1	2	3
Total other income	19	10	14
Civic and political expenditures	(10)	(14)	(5)
Donations	(1)	(15)	(4)
All other	(6)	(6)	(7)
Total other expense	$ (17)	$ (35)	$ (16)