Schedule I - Condensed Financial Information of Registrant (Condensed Statements of Income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012		Dec. 31, 2011
Other operating expense									$ (1,236)	$ (1,224)		$ (1,237)
General taxes									234	229		205
Total operating expenses									(5,424)	(5,250)		(5,500)
Operating Loss	264	317	232	329	212	343	260	188	1,142	1,003		1,003
Interest income									3	5		9
Total other income (expense)									12	8		18
Interest on long-term debt									385	372		396
Intercompany interest expense and other									16	21		23
Total interest charges									398	389		415
Income Before Income Taxes									756	622		606
Income Tax Benefit									302	245		191
Income From Continuing Operations	102	127	81	144	67	149	101	60	454	377		415
Income From Discontinued Operations, Net								7		7	[1]	2	[2]
Net Income Available to Common Stockholders	102	126	80	144	67	148	100	67	452	382		415
CMS Energy [Member]
Other operating expense									(6)	(8)		(9)
General taxes												6
Total operating expenses									(6)	(8)		(3)
Operating Loss									(6)	(8)		(3)
Equity earnings of subsidiaries									566	477		510
Interest income									1	1		1
Other expense									(8)	(5)		(5)
Total other income (expense)									559	473		506
Interest on long-term debt									148	140		143
Intercompany interest expense and other									3	5		6
Total interest charges									151	145		149
Income Before Income Taxes									402	320		354
Income Tax Benefit									(50)	(62)		(61)
Income From Continuing Operations									452	382		415
Net Income Available to Common Stockholders									$ 452	$ 382		$ 415

[1] Includes an $11 million ($7 million net of tax) reversal of a loss on disposal due to the elimination of a liability associated with the 2003 sale of Panhandle.

[2] Includes an operating gain of $3 million related to a litigation settlement at CMS Viron.