Consolidated Balance Sheets - USD ($) $ in Millions		Dec. 31, 2017	Dec. 31, 2016
Current Assets
Cash and cash equivalents		$ 182	$ 235
Restricted cash and cash equivalents		17	19
Accounts receivable and accrued revenue, less allowance		1,032	821
Notes receivable, less allowance		198	180
Notes receivable held for sale		2	39
Accounts receivable - related parties		12	12
Inventories at average cost
Gas in underground storage		458	446
Materials and supplies		133	119
Generating plant fuel stock		81	61
Deferred property taxes		257	250
Regulatory assets		20	17
Prepayments and other current assets		83	81
Total current assets		2,475	2,280
Plant, Property, and Equipment
Plant, property, and equipment, gross		22,506	21,010
Less accumulated depreciation and amortization		6,510	6,056
Plant, property, and equipment, net		15,996	14,954
Construction work in progress		765	761
Total plant, property, and equipment	[1]	16,761	15,715
Other Non-current Assets
Regulatory assets		1,764	2,091
Accounts and notes receivable		1,187	1,118
Investments	[2]	64	65
Other		799	353
Total other non-current assets		3,814	3,627
Total Assets		23,050	21,622
Current Liabilities
Current portion of long-term debt, capital leases, and financing obligation		1,103	886
Notes payable		170	398
Accounts payable		725	598
Accounts payable - related parties		15	12
Accrued rate refunds		33	21
Accrued interest		103	98
Accrued taxes		360	348
Regulatory liabilities		80	95
Other current liabilities		195	199
Total current liabilities		2,784	2,655
Non-current Liabilities
Long-term debt		9,123	8,640
Non-current portion of capital leases and financing obligation		91	110
Regulatory liabilities		3,715	2,041
Postretirement benefits		766	789
Asset retirement obligations		430	447
Deferred investment tax credit		87	73
Deferred income taxes		1,269	2,287
Other non-current liabilities		307	290
Total non-current liabilities		15,788	14,677
Commitments and Contingencies (Notes 3 and 4)
Common stockholder's equity
Common stock		3	3
Other paid-in capital		5,019	4,916
Accumulated other comprehensive loss		(50)	(50)
Retained earnings (Accumulated deficit)		(531)	(616)
Total common stockholders' equity		4,441	4,253
Noncontrolling interests		37	37
Total equity		4,478	4,290
Total Liabilities and Equity		23,050	21,622
Consumers Energy Company [Member]
Current Assets
Cash and cash equivalents		44	131
Restricted cash and cash equivalents		17	19
Accounts receivable and accrued revenue, less allowance		885	800
Notes receivable, less allowance		17	29
Accounts receivable - related parties		2	9
Inventories at average cost
Gas in underground storage		458	446
Materials and supplies		128	114
Generating plant fuel stock		76	57
Deferred property taxes		257	250
Regulatory assets		20	17
Prepayments and other current assets		71	70
Total current assets		1,975	1,942
Plant, Property, and Equipment
Plant, property, and equipment, gross		22,318	20,838
Less accumulated depreciation and amortization		6,441	5,994
Plant, property, and equipment, net		15,877	14,844
Construction work in progress		753	759
Total plant, property, and equipment	[1]	16,630	15,603
Other Non-current Assets
Regulatory assets		1,764	2,091
Accounts and notes receivable		22	27
Investments		21	33
Other		687	250
Total other non-current assets		2,494	2,401
Total Assets		21,099	19,946
Current Liabilities
Current portion of long-term debt, capital leases, and financing obligation		365	397
Notes payable		170	398
Accounts payable		701	580
Accounts payable - related parties		19	18
Accrued rate refunds		33	21
Accrued interest		67	67
Accrued taxes		542	354
Regulatory liabilities		80	95
Other current liabilities		159	164
Total current liabilities		2,136	2,094
Non-current Liabilities
Long-term debt		5,561	5,253
Non-current portion of capital leases and financing obligation		91	110
Regulatory liabilities		3,715	2,041
Postretirement benefits		711	730
Asset retirement obligations		429	446
Deferred investment tax credit		87	73
Deferred income taxes		1,640	3,042
Other non-current liabilities		241	218
Total non-current liabilities		12,475	11,913
Commitments and Contingencies (Notes 3 and 4)
Common stockholder's equity
Common stock		841	841
Other paid-in capital		4,449	3,999
Accumulated other comprehensive loss		(12)	(3)
Retained earnings (Accumulated deficit)		1,173	1,065
Total common stockholders' equity		6,451	5,902
Preferred stock		37	37
Total equity		6,488	5,939
Total Liabilities and Equity		$ 21,099	$ 19,946

[1] For the year ended December 31, 2017, Consumers' plant additions were $1.7 billion and plant retirements were $214 million. For the year ended December 31, 2016, Consumers' plant additions were $2.3 billion and plant retirements were $285 million.

[2] Consumers had no significant equity method investments.