Consolidated Balance Sheets (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Current Assets
Cash and cash equivalents	$ 758	$ 172
Restricted cash and cash equivalents	31	32
Accounts receivable and accrued revenue, less allowances	1,032	914
Notes receivable	69	63
Accounts receivable - related parties	10	10
Accrued power supply and gas revenue	188
Inventories at average cost
Gas in underground storage	340	660
Materials and supplies	112	107
Generating plant fuel stock	85	114
Deferred income taxes	42	126
Deferred property taxes	167	202
Regulatory assets	16	40
Prepayments and other current assets	119	86
Total current assets	2,969	2,526
Plant, Property, and Equipment
Plant, property, and equipment, gross	16,322	16,184
Less accumulated depreciation and amortization	5,168	5,087
Plant, property, and equipment, net	11,154	11,097
Construction work in progress	1,206	1,149
Total plant, property, and equipment	12,360	12,246
Other Non-current Assets
Regulatory assets	1,496	1,530
Accounts and notes receivable, less allowances	646	646
Investments	61	59
Other	392	409
Total other non-current assets	2,595	2,644
Total Assets	17,924	17,416
Current Liabilities
Current portion of long-term debt, capital and financing obligations	666	562
Notes payable		170
Accounts payable	632	585
Accounts payable - related parties	10	10
Accrued rate refunds		12
Accrued interest	67	96
Accrued taxes	225	297
Regulatory liabilities	70	67
Other current liabilities	131	146
Total current liabilities	1,801	1,945
Non-current Liabilities
Long-term debt	7,536	7,101
Non-current portion of capital and financing obligations	135	138
Regulatory liabilities	2,236	2,215
Postretirement benefits	240	239
Asset retirement obligations	328	325
Deferred investment tax credit	39	40
Deferred income taxes	1,647	1,616
Other non-current liabilities	307	306
Total non-current liabilities	12,468	11,980
Commitments and Contingencies (Notes 1 and 2)
Equity
Common stock	3	3
Other paid-in capital	4,746	4,715
Accumulated other comprehensive loss	(21)	(22)
Retained earnings (Accumulated deficit)	(1,110)	(1,242)
Total common stockholders equity	3,618	3,454
Noncontrolling interests	37	37
Total equity	3,655	3,491
Total Liabilities and Equity	17,924	17,416
Consumers Energy Company [Member]
Current Assets
Cash and cash equivalents	178	18
Restricted cash and cash equivalents	31	31
Accounts receivable and accrued revenue, less allowances	1,013	902
Notes receivable		14
Accounts receivable - related parties	1	4
Accrued power supply and gas revenue	188
Inventories at average cost
Gas in underground storage	340	653
Materials and supplies	107	103
Generating plant fuel stock	84	113
Deferred property taxes	167	202
Regulatory assets	16	40
Prepayments and other current assets	111	77
Total current assets	2,236	2,157
Plant, Property, and Equipment
Plant, property, and equipment, gross	16,181	16,044
Less accumulated depreciation and amortization	5,102	5,022
Plant, property, and equipment, net	11,079	11,022
Construction work in progress	1,204	1,147
Total plant, property, and equipment	12,283	12,169
Other Non-current Assets
Regulatory assets	1,496	1,530
Accounts and notes receivable, less allowances	2	11
Investments	32	29
Other	263	283
Total other non-current assets	1,793	1,853
Total Assets	16,312	16,179
Current Liabilities
Current portion of long-term debt, capital and financing obligations	65	64
Notes payable		170
Accounts payable	611	571
Accounts payable - related parties	16	13
Accrued rate refunds		12
Accrued interest	43	63
Accrued taxes	343	353
Deferred income taxes	94	55
Regulatory liabilities	70	67
Other current liabilities	101	112
Total current liabilities	1,343	1,480
Non-current Liabilities
Long-term debt	4,567	4,579
Non-current portion of capital and financing obligations	135	138
Regulatory liabilities	2,236	2,215
Postretirement benefits	180	179
Asset retirement obligations	327	324
Deferred investment tax credit	39	40
Deferred income taxes	2,137	2,115
Other non-current liabilities	253	252
Total non-current liabilities	9,874	9,842
Commitments and Contingencies (Notes 1 and 2)
Equity
Common stock	841	841
Other paid-in capital	3,407	3,257
Accumulated other comprehensive loss		(2)
Retained earnings (Accumulated deficit)	810	724
Total common stockholders equity	5,058	4,820
Preferred stock	37	37
Total equity	5,095	4,857
Total Liabilities and Equity	$ 16,312	$ 16,179