Schedule I - Condensed Financial Information of Registrant (Condensed Balance Sheets) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash and cash equivalents	$ 172	$ 93	$ 161	$ 247
Notes and accrued interest receivable	63	41
Accounts receivable, including intercompany and related parties	10	10
Deferred income taxes	126
Total current assets	2,526	2,422
Less accumulated depreciation and amortization	5,087	5,121
Other	409	293
Total other non-current assets	2,644	3,158
Total Assets	17,416	17,131	16,452
Current portion of long-term debt	562	541
Accounts and notes payable, including intercompany and related parties	10	9
Accrued interest, including intercompany	96	95
Accrued taxes	297	279
Other liabilities current	146	152
Total current liabilities	1,945	1,797
Long-term debt	7,101	6,710
Unamortized Discount	12	16
Postretirement benefits	239	1,451
Other non-current liabilities	306	311
Total non-current liabilities	11,980	12,096
Common stockholders' equity	3,454	3,194
Total Liabilities and Equity	17,416	17,131
CMS Energy [Member]
Cash and cash equivalents		2
Notes and accrued interest receivable	1	1
Accounts receivable, including intercompany and related parties	7	4
Accrued taxes		7
Deferred income taxes	2	3
Total current assets	10	17
Plant, property, and equipment, gross	16	16
Less accumulated depreciation and amortization	16	16
Total plant, property and equipment
Deferred income taxes	345	392
Invetment in subsidiaries	5,626	5,312
Other investments - DB SERP	23	24
Other	23	26
Total other non-current assets	6,017	5,754
Total Assets	6,027	5,771
Current portion of long-term debt	172	172
Accounts and notes payable, including intercompany and related parties	107	152
Accrued interest, including intercompany	32	30
Accrued taxes	41
Other liabilities current	4	5
Total current liabilities	356	359
Long-term debt	2,205	2,205
Unamortized Discount	(9)	(13)
Postretirement benefits	19	24
Other non-current liabilities	2	2
Total non-current liabilities	2,217	2,218
Common stockholders' equity	3,454	3,194
Total Liabilities and Equity	$ 6,027	$ 5,771