Financings And Capitalization (Narrative) (Details) (USD $)			6 Months Ended	1 Months Ended	6 Months Ended		6 Months Ended	15 Months Ended
	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2014 CMS Energy [Member]	Jun. 30, 2014 Consumers Energy Company [Member]	Jun. 30, 2014 Consumers Energy Company [Member]	Dec. 31, 2013 Consumers Energy Company [Member]	Jun. 30, 2014 Short-Term Borrowings [Member] Consumers Energy Company [Member]	Jun. 30, 2014 Continuous Equity Program [Member]	Jul. 31, 2014 Securitization Bond Due 2020 [Member] Consumers Energy Company [Member] Subsequent Event [Member]	Jul. 31, 2014 Securitization Bond Due 2025 [Member] Consumers Energy Company [Member] Subsequent Event [Member]	Jul. 31, 2014 Securitization Bond Due 2029 [Member] Consumers Energy Company [Member] Subsequent Event [Member]
Financing And Capitalization [Line Items]
Long-term debt	$ 7,535,000,000	$ 7,101,000,000		$ 4,555,000,000	$ 4,555,000,000	$ 4,579,000,000			$ 124,000,000	$ 139,000,000	$ 115,000,000
Interest rate									1.334%	2.962%	3.528%
Maximum allowed short term securities outstanding under FERC Authorization				800,000,000	800,000,000
Amount of accounts receivable eligible for transfer							250,000,000
Average short-term borrowings							22,000,000
Weighted average annual interest rate							0.85%
Limitation on payment of stock dividends	3,600,000,000
Unrestricted retained earnings				735,000,000	735,000,000
Common stock dividends from Consumers			255,000,000
Aggregate sales price of an equity offering program								50,000,000
Accounts receivable sales facility, remaining borrowing capacity							250,000,000
Maximum limitation on outstanding securities				$ 1,900,000,000
Expiration date of authorizations					June 30, 2016