Consolidated Statements Of Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating Revenue	$ 1,829	$ 1,801
Operating Expenses
Fuel for electric generation	117	125
Purchased and interchange power	333	346
Purchased power - related parties	22	22
Cost of gas sold	336	354
Maintenance and other operating expenses	290	303
Depreciation and amortization	262	238
General taxes	81	87
Total operating expenses	1,441	1,475
Operating Income	388	326
Other Income (Expense)
Interest income	5	1
Allowance for equity funds used during construction	2	3
Income from equity method investees	4	4
Nonoperating retirement benefits, net	3	10
Other income	2	3
Other expense	(2)	(3)
Total other income	14	18
Interest Charges
Interest on long-term debt	100	100
Other interest expense	8	7
Allowance for borrowed funds used during construction	(1)	(1)
Total interest charges	107	106
Income Before Income Taxes	295	238
Income Tax Expense	96	74
Net Income	$ 199	$ 164
Basic Earnings Per Average Common Share	$ 0.71	$ 0.59
Diluted Earnings Per Average Common Share	0.71	0.59
Dividends Declared Per Common Share	$ 0.33	$ 0.31
Consumers Energy Company [Member]
Operating Revenue	$ 1,737	$ 1,723
Operating Expenses
Fuel for electric generation	89	99
Purchased and interchange power	331	343
Purchased power - related parties	22	22
Cost of gas sold	332	351
Maintenance and other operating expenses	265	278
Depreciation and amortization	260	237
General taxes	79	85
Total operating expenses	1,378	1,415
Operating Income	359	308
Other Income (Expense)
Interest income	4	1
Allowance for equity funds used during construction	2	3
Nonoperating retirement benefits, net	3	9
Other income	14	3
Other expense	(2)	(3)
Total other income	21	13
Interest Charges
Interest on long-term debt	66	65
Other interest expense	3	3
Allowance for borrowed funds used during construction	(1)	(1)
Total interest charges	68	67
Income Before Income Taxes	312	254
Income Tax Expense	101	82
Net Income	$ 211	$ 172