Long-Term Debt (Debt Redemptions) (Details) - Jun. 30, 2015 - USD ($) $ in Millions	Total
Debt Instrument [Line Items]
Debt redemption amount	$ 118
Securitization Bonds | DTE Electric | March 2015 Securitization Bonds 6.62% due 2015
Debt Instrument [Line Items]
Interest Rate	6.62%
Debt redemption amount	$ 105
Mortgages | DTE Electric | 7.904% Mortgage Bonds Due 2016
Debt Instrument [Line Items]
Interest Rate	7.904%
Debt redemption amount	$ 10
Other Long Term Debt | Various Other Long Term Debt Due 2015
Debt Instrument [Line Items]
Debt redemption amount	$ 3