Consolidated Balance Sheets - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Current Assets
Cash and cash equivalents	$ 418	$ 235
Restricted cash and cash equivalents	17	19
Accounts receivable and accrued revenue, less allowance	666	821
Notes receivable, less allowance	193	180
Notes receivable held for sale	18	39
Accounts receivable - related parties	12	12
Inventories at average cost
Gas in underground storage	395	446
Materials and supplies	121	119
Generating plant fuel stock	66	61
Deferred property taxes	179	250
Regulatory assets	9	17
Prepayments and other current assets	117	81
Total current assets	2,211	2,280
Plant, Property, and Equipment
Plant, property, and equipment, gross	21,628	21,010
Less accumulated depreciation and amortization	6,311	6,056
Plant, property, and equipment, net	15,317	14,954
Construction work in progress	802	761
Total plant, property, and equipment	16,119	15,715
Other Non-current Assets
Regulatory assets	2,050	2,091
Accounts and notes receivable	1,125	1,118
Investments	68	65
Other	294	353
Total other non-current assets	3,537	3,627
Total Assets	21,867	21,622
Current Liabilities
Current portion of long-term debt, capital leases, and financing obligation	840	886
Notes payable		398
Accounts payable	599	598
Accounts payable - related parties	9	12
Accrued rate refunds	77	21
Accrued interest	104	98
Accrued taxes	256	348
Regulatory liabilities	85	95
Other current liabilities	145	199
Total current liabilities	2,115	2,655
Non-current Liabilities
Long-term debt	9,091	8,640
Non-current portion of capital leases and financing obligation	99	110
Regulatory liabilities	2,054	2,041
Postretirement benefits	770	789
Asset retirement obligations	452	447
Deferred investment tax credit	89	73
Deferred income taxes	2,422	2,287
Other non-current liabilities	289	290
Total non-current liabilities	15,266	14,677
Commitments and Contingencies (Notes 2 and 3)
Common stockholder's equity
Common stock	3	3
Other paid-in capital	5,006	4,916
Accumulated other comprehensive loss	(48)	(50)
Retained earnings (Accumulated deficit)	(512)	(616)
Total common stockholders' equity	4,449	4,253
Noncontrolling interests	37	37
Total equity	4,486	4,290
Total Liabilities and Equity	21,867	21,622
Consumers Energy Company [Member]
Current Assets
Cash and cash equivalents	343	131
Restricted cash and cash equivalents	17	19
Accounts receivable and accrued revenue, less allowance	648	800
Notes receivable, less allowance	30	29
Accounts receivable - related parties	2	9
Inventories at average cost
Gas in underground storage	395	446
Materials and supplies	116	114
Generating plant fuel stock	63	57
Deferred property taxes	179	250
Regulatory assets	9	17
Prepayments and other current assets	110	70
Total current assets	1,912	1,942
Plant, Property, and Equipment
Plant, property, and equipment, gross	21,451	20,838
Less accumulated depreciation and amortization	6,246	5,994
Plant, property, and equipment, net	15,205	14,844
Construction work in progress	801	759
Total plant, property, and equipment	16,006	15,603
Other Non-current Assets
Regulatory assets	2,050	2,091
Accounts and notes receivable	28	27
Investments	20	33
Other	189	250
Total other non-current assets	2,287	2,401
Total Assets	20,205	19,946
Current Liabilities
Current portion of long-term debt, capital leases, and financing obligation	394	397
Notes payable		398
Accounts payable	580	580
Accounts payable - related parties	15	18
Accrued rate refunds	77	21
Accrued interest	67	67
Accrued taxes	257	354
Regulatory liabilities	85	95
Other current liabilities	108	164
Total current liabilities	1,583	2,094
Non-current Liabilities
Long-term debt	5,339	5,253
Non-current portion of capital leases and financing obligation	99	110
Regulatory liabilities	2,054	2,041
Postretirement benefits	712	730
Asset retirement obligations	451	446
Deferred investment tax credit	89	73
Deferred income taxes	3,197	3,042
Other non-current liabilities	219	218
Total non-current liabilities	12,160	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)	1,143	1,065
Total common stockholders' equity	6,425	5,902
Preferred stock	37	37
Total equity	6,462	5,939
Total Liabilities and Equity	$ 20,205	$ 19,946