Consolidated Statements Of Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Operating Revenue	$ 1,486	$ 1,430	$ 4,947	$ 5,421
Operating Expenses
Fuel for electric generation	161	161	462	534
Purchased and interchange power	392	387	1,082	1,244
Purchased power - related parties	21	21	61	67
Cost of gas sold	52	86	754	1,107
Maintenance and other operating expenses	311	329	906	899
Depreciation and amortization	173	153	564	503
General taxes	59	57	200	188
Total operating expenses	1,169	1,194	4,029	4,542
Operating Income	317	236	918	879
Other Income (Expense)
Interest income	1	1	3	2
Allowance for equity funds used during construction	3	2	7	6
Income from equity method investees	4	4	9	11
Other income	2	2	8	8
Other expense	(3)	(3)	(11)	(26)
Total other income (expense)	7	6	16	1
Interest Charges
Interest on long-term debt	95	98	288	294
Other interest expense	7	4	20	12
Allowance for borrowed funds used during construction	(1)	(1)	(3)	(3)
Total interest charges	101	101	305	303
Income Before Income Taxes	223	141	629	577
Income Tax Expense	75	47	211	195
Net Income	148	94	418	382
Income Attributable to Noncontrolling Interests			1	1
Net Income Available to Common Stockholders	$ 148	$ 94	$ 417	$ 381
Basic Earnings Per Average Common Share	$ 0.53	$ 0.34	$ 1.51	$ 1.41
Diluted Earnings Per Average Common Share	0.53	0.34	1.51	1.39
Dividends declared per common share	$ 0.29	$ 0.27	$ 0.87	$ 0.81
Consumers Energy Company [Member]
Operating Revenue	$ 1,417	$ 1,359	$ 4,726	$ 5,128
Operating Expenses
Fuel for electric generation	138	137	381	455
Purchased and interchange power	389	382	1,072	1,214
Purchased power - related parties	21	21	61	67
Cost of gas sold	46	71	737	1,006
Maintenance and other operating expenses	289	296	845	834
Depreciation and amortization	172	152	560	498
General taxes	57	55	194	183
Total operating expenses	1,112	1,114	3,850	4,257
Operating Income	305	245	876	871
Other Income (Expense)
Interest income	1	1	3	2
Interest and dividend income - related parties		1		1
Allowance for equity funds used during construction	3	2	7	6
Other income	2	2	17	8
Other expense	(3)	(3)	(11)	(13)
Total other income (expense)	3	3	16	4
Interest Charges
Interest on long-term debt	62	62	188	180
Other interest expense	4	3	11	8
Allowance for borrowed funds used during construction	(1)	(1)	(3)	(3)
Total interest charges	65	64	196	185
Income Before Income Taxes	243	184	696	690
Income Tax Expense	83	65	237	241
Net Income	160	119	459	449
Preferred Stock Dividends			1	1
Net Income Available to Common Stockholders	$ 160	$ 119	$ 458	$ 448