Consolidated Statements Of Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Operating Revenue	$ 1,350	$ 1,468	$ 3,461	$ 3,991
Operating Expenses
Fuel for electric generation	134	154	301	373
Purchased and interchange power	341	359	690	857
Purchased power - related parties	17	22	40	46
Cost of gas sold	113	187	702	1,021
Maintenance and other operating expenses	312	304	595	570
Depreciation and amortization	169	151	391	350
General taxes	60	56	141	131
Total operating expenses	1,146	1,233	2,860	3,348
Operating Income	204	235	601	643
Other Income (Expense)
Interest income	1	1	2	1
Allowance for equity funds used during construction	2	2	4	4
Income from equity method investees	1	3	5	7
Other income	3	3	6	6
Other expense	(4)	(16)	(8)	(23)
Total other income (expense)	3	(7)	9	(5)
Interest Charges
Interest on long-term debt	97	99	193	196
Other interest expense	7	3	13	8
Allowance for borrowed funds used during construction	(1)	(1)	(2)	(2)
Total interest charges	103	101	204	202
Income (Loss) Before Income Taxes	104	127	406	436
Income Tax Expense (Benefit)	36	43	136	148
Net Income (Loss)	68	84	270	288
Income attributable to noncontrolling interests	1	1	1	1
Net Income (Loss) Available to Common Stockholders	$ 67	$ 83	$ 269	$ 287
Basic Earnings Per Average Common Share	$ 0.25	$ 0.31	$ 0.98	$ 1.07
Diluted Earnings Per Average Common Share	0.25	0.30	0.98	1.05
Dividends declared per common share	$ 0.29	$ 0.27	$ 0.58	$ 0.54
Consumers Energy Company [Member]
Operating Revenue	$ 1,281	$ 1,387	$ 3,309	$ 3,769
Operating Expenses
Fuel for electric generation	110	132	243	318
Purchased and interchange power	337	348	683	832
Purchased power - related parties	17	22	40	46
Cost of gas sold	108	167	691	935
Maintenance and other operating expenses	291	288	556	538
Depreciation and amortization	168	149	388	346
General taxes	58	54	137	128
Total operating expenses	1,089	1,160	2,738	3,143
Operating Income	192	227	571	626
Other Income (Expense)
Interest income	1	1	2	1
Allowance for equity funds used during construction	2	2	4	4
Other income	3	3	15	6
Other expense	(4)	(4)	(8)	(10)
Total other income (expense)	2	2	13	1
Interest Charges
Interest on long-term debt	63	59	126	118
Other interest expense	4	2	7	5
Allowance for borrowed funds used during construction	(1)	(1)	(2)	(2)
Total interest charges	66	60	131	121
Income (Loss) Before Income Taxes	128	169	453	506
Income Tax Expense (Benefit)	44	60	154	176
Net Income (Loss)	84	109	299	330
Preferred Stock Dividends and Distribution	1	1	1	1
Net Income Attributable to Common Stockholder	$ 83	$ 108	$ 298	$ 329