Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Current Assets
Cash and cash equivalents	$ 142	$ 235
Restricted cash and cash equivalents	27	19
Accounts receivable and accrued revenue, less allowance	631	821
Notes receivable, less allowance	197	180
Notes receivable held for sale	31	39
Accounts receivable - related parties	12	12
Inventories at average cost
Gas in underground storage	584	446
Materials and supplies	126	119
Generating plant fuel stock	77	61
Deferred property taxes	157	250
Regulatory assets	19	17
Prepayments and other current assets	118	81
Total current assets	2,121	2,280
Plant, Property, and Equipment
Plant, property, and equipment, gross	21,966	21,010
Less accumulated depreciation and amortization	6,403	6,056
Plant, property, and equipment, net	15,563	14,954
Construction work in progress	881	761
Total plant, property, and equipment	16,444	15,715
Other Non-current Assets
Regulatory assets	2,038	2,091
Accounts and notes receivable	1,177	1,118
Investments	71	65
Other	269	353
Total other non-current assets	3,555	3,627
Total Assets	22,120	21,622
Current Liabilities
Current portion of long-term debt, capital leases, and financing obligation	980	886
Notes payable	230	398
Accounts payable	624	598
Accounts payable - related parties	8	12
Accrued rate refunds	35	21
Accrued interest	79	98
Accrued taxes	90	348
Regulatory liabilities	85	95
Other current liabilities	130	199
Total current liabilities	2,261	2,655
Non-current Liabilities
Long-term debt	9,024	8,640
Non-current portion of capital leases and financing obligation	97	110
Regulatory liabilities	2,066	2,041
Postretirement benefits	760	789
Asset retirement obligations	443	447
Deferred investment tax credit	88	73
Deferred income taxes	2,501	2,287
Other non-current liabilities	308	290
Total non-current liabilities	15,287	14,677
Commitments and Contingencies (Notes 2 and 3)
Common stockholder's equity
Common stock	3	3
Other paid-in capital	5,013	4,916
Accumulated other comprehensive loss	(47)	(50)
Retained earnings (Accumulated deficit)	(434)	(616)
Total common stockholders' equity	4,535	4,253
Noncontrolling interests	37	37
Total equity	4,572	4,290
Total Liabilities and Equity	22,120	21,622
Consumers Energy Company [Member]
Current Assets
Cash and cash equivalents	55	131
Restricted cash and cash equivalents	27	19
Accounts receivable and accrued revenue, less allowance	612	800
Notes receivable, less allowance	30	29
Accounts receivable - related parties	2	9
Inventories at average cost
Gas in underground storage	584	446
Materials and supplies	121	114
Generating plant fuel stock	73	57
Deferred property taxes	157	250
Regulatory assets	19	17
Prepayments and other current assets	110	70
Total current assets	1,790	1,942
Plant, Property, and Equipment
Plant, property, and equipment, gross	21,784	20,838
Less accumulated depreciation and amortization	6,335	5,994
Plant, property, and equipment, net	15,449	14,844
Construction work in progress	877	759
Total plant, property, and equipment	16,326	15,603
Other Non-current Assets
Regulatory assets	2,038	2,091
Accounts and notes receivable	45	27
Investments	21	33
Other	160	250
Total other non-current assets	2,264	2,401
Total Assets	20,380	19,946
Current Liabilities
Current portion of long-term debt, capital leases, and financing obligation	464	397
Notes payable	230	398
Accounts payable	601	580
Accounts payable - related parties	12	18
Accrued rate refunds	35	21
Accrued interest	48	67
Accrued taxes	111	354
Regulatory liabilities	85	95
Other current liabilities	93	164
Total current liabilities	1,679	2,094
Non-current Liabilities
Long-term debt	5,275	5,253
Non-current portion of capital leases and financing obligation	97	110
Regulatory liabilities	2,066	2,041
Postretirement benefits	703	730
Asset retirement obligations	442	446
Deferred investment tax credit	88	73
Deferred income taxes	3,257	3,042
Other non-current liabilities	241	218
Total non-current liabilities	12,169	11,913
Commitments and Contingencies (Notes 2 and 3)
Common stockholder's equity
Common stock	841	841
Other paid-in capital	4,449	3,999
Accumulated other comprehensive loss	(8)	(3)
Retained earnings (Accumulated deficit)	1,213	1,065
Total common stockholders' equity	6,495	5,902
Preferred stock	37	37
Total equity	6,532	5,939
Total Liabilities and Equity	$ 20,380	$ 19,946