Financings And Capitalization (Narrative) (Details) (USD $)		3 Months Ended		3 Months Ended	12 Months Ended
	Mar. 31, 2014	Mar. 31, 2014 CMS Energy [Member]	Mar. 31, 2014 Consumers Energy Company [Member]	Mar. 31, 2014 Short-Term Borrowings [Member] Consumers Energy Company [Member]	Mar. 31, 2014 Continuous Equity Program [Member]	Mar. 31, 2014 Senior Notes 5.5% Due June 2029 [Member]
Financing And Capitalization [Line Items]
Amount of accounts receivable eligible for transfer				$ 250,000,000
Average short-term borrowings				44,000,000
Weighted average annual interest rate				0.85%
Number of trading days, adjusted trigger price contingencies were met						20 days
Number of trading days						30 days
Limitation on payment of stock dividends	3,600,000,000
Unrestricted retained earnings			747,000,000
Common stock dividends from Consumers		135,000,000
Aggregate sales price of an equity offering program					50,000,000
Accounts receivable sales facility, remaining borrowing capacity				$ 250,000,000