Consolidated Balance Sheets (USD $) In Millions	Sep. 30, 2011	Dec. 31, 2010
Assets
Cash and cash equivalents	$ 623	$ 247
Restricted cash and cash equivalents	29	23
Accounts receivable and accrued revenue, less allowances	690	981
Notes receivable	62	70
Accounts receivable - related parties	10	10
Accrued power supply revenue	0	15
Inventories at average cost
Gas in underground storage	1,050	946
Materials and supplies	102	104
Generating plant fuel stock	127	125
Deferred property taxes	116	180
Regulatory assets	2	19
Assets held for sale	0	2
Prepayments and other current assets	49	37
Total current assets	2,860	2,759
Plant, Property and Equipment (at cost)
Plant, property, and equipment, gross	14,607	14,145
Less accumulated depreciation, depletion, and amortization	4,869	4,646
Plant, property and equipment, net	9,738	9,499
Construction work in progress	672	570
Total plant, property and equipment	10,410	10,069
Non-current Assets
Regulatory assets	2,002	2,093
Accounts and notes receivable, less allowances	430	397
Investments	53	49
Assets held for sale		4
Other non-current assets	203	245
Total non-current assets	2,688	2,788
Total Assets	15,958	15,616
Liabilities and Equity
Current portion of long-term debt, capital and finance lease obligations	1,140	750
Accounts payable	484	492
Accounts payable - related parties	9	9
Accrued rate refunds	24	19
Accrued interest	70	102
Accrued taxes	103	302
Deferred income taxes	132	180
Regulatory liabilities	121	22
Liabilities held for sale		1
Other current liabilities	131	144
Total current liabilities	2,214	2,021
Non-current Liabilities
Long-term debt	6,037	6,448
Non-current portion of capital and finance lease obligations	171	188
Regulatory liabilities	1,874	1,988
Postretirement benefits	1,139	1,135
Asset retirement obligations	254	245
Deferred investment tax credit	47	49
Deferred income taxes	870	438
Other non-current liabilities	265	267
Total non-current liabilities	10,657	10,758
Commitments and Contingencies (Notes 3, 4, 5, 7, and 8)
Equity
Common stock	3	2
Other paid-in capital	4,622	4,588
Accumulated other comprehensive loss	(40)	(40)
Retained earnings (Accumulated deficit)	(1,542)	(1,757)
Total common stockholders' equity	3,043	2,793
Noncontrolling interests	44	44
Total equity	3,087	2,837
Total Liabilities and Equity	15,958	15,616
Consumers Energy Company [Member]
Assets
Cash and cash equivalents	373	71
Restricted cash and cash equivalents	28	23
Accounts receivable and accrued revenue, less allowances	683	963
Notes receivable	43	55
Accounts receivable - related parties	2	1
Accrued power supply revenue	0	15
Inventories at average cost
Gas in underground storage	1,050	941
Materials and supplies	98	100
Generating plant fuel stock	125	124
Deferred property taxes	116	180
Regulatory assets	2	19
Prepayments and other current assets	43	27
Total current assets	2,563	2,519
Plant, Property and Equipment (at cost)
Plant, property, and equipment, gross	14,475	14,022
Less accumulated depreciation, depletion, and amortization	4,814	4,593
Plant, property and equipment, net	9,661	9,429
Construction work in progress	671	566
Total plant, property and equipment	10,332	9,995
Non-current Assets
Regulatory assets	2,002	2,093
Accounts and notes receivable, less allowances	7	22
Investments	31	34
Other non-current assets	123	176
Total non-current assets	2,163	2,325
Total Assets	15,058	14,839
Liabilities and Equity
Current portion of long-term debt, capital and finance lease obligations	362	61
Accounts payable	473	471
Accounts payable - related parties	12	11
Accrued rate refunds	24	19
Accrued interest	41	74
Accrued taxes	102	199
Deferred income taxes	154	209
Regulatory liabilities	121	22
Other current liabilities	94	95
Total current liabilities	1,383	1,161
Non-current Liabilities
Long-term debt	3,997	4,488
Non-current portion of capital and finance lease obligations	171	188
Regulatory liabilities	1,874	1,988
Postretirement benefits	1,081	1,076
Asset retirement obligations	253	244
Deferred investment tax credit	47	49
Deferred income taxes	1,663	1,289
Other non-current liabilities	178	176
Total non-current liabilities	9,264	9,498
Commitments and Contingencies (Notes 3, 4, 5, 7, and 8)
Equity
Common stock	841	841
Other paid-in capital	2,957	2,832
Retained earnings (Accumulated deficit)	569	463
Total common stockholders' equity	4,367	4,136
Preferred stock	44	44
Total equity	4,411	4,180
Total Liabilities and Equity	$ 15,058	$ 14,839