Financings And Capitalization (Major Long-Term Debt Transactions) (Details) (CMS Energy [Member], USD $)	1 Months Ended		3 Months Ended
	Apr. 24, 2014 Senior Notes 6.875% Due December 2015 [Member] Subsequent Event [Member]	Mar. 31, 2014 Debt Issuance [Member]	Mar. 31, 2014 Debt Issuance [Member] Senior Notes 3.875% Due March 2024 [Member]		Mar. 31, 2014 Debt Issuance [Member] Senior Notes 4.875% Due March 2044 [Member]
Debt Instrument [Line Items]
Debt issuance, principal		$ 550,000,000	$ 250,000,000	[1]	$ 300,000,000	[1]
Debt retirement, principal	$ 125,000,000
Interest rate	6.875%		3.875%	[1]	4.875%	[1]
Debt issuance date			February 2014	[1]	February 2014	[1]
Maturity date	December 2015		March 2024	[1]	March 2044	[1]

[1] In April 2014, CMS Energy used a portion of these proceeds to retire its $125 million 6.875 percent Senior Notes due December 2015. CMS Energy intends to use the remaining proceeds to retire existing debt and for general corporate purposes.