Long-Term Debt (Debt Redemptions) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
Debt Instrument, Redemption [Line Items]
Extinguishment of debt	$ 1,237
Mortgages [Member] | Electric [Member] | March 2014 Mortgage Bonds Various Interest Rates Maturing in 2014 [Member]
Debt Instrument, Redemption [Line Items]
Extinguishment of debt	13
Mortgages [Member] | Gas [Member] | May 2014 Mortgage Bonds 8.25% Maturing in 2014 [Member]
Debt Instrument, Redemption [Line Items]
Debt instrument stated interest rate	8.25%
Extinguishment of debt	80
Senior Notes [Member] | Electric [Member] | July 2014 Senior Notes 4.80% Maturing in 2015 [Member]
Debt Instrument, Redemption [Line Items]
Debt instrument stated interest rate	4.80%
Extinguishment of debt	200
Senior Notes [Member] | Electric [Member] | August 2014 Senior Notes 5.40% Maturing in 2014 [Member]
Debt Instrument, Redemption [Line Items]
Debt instrument stated interest rate	5.40%
Extinguishment of debt	200
Senior Notes [Member] | DTE Energy [Member] | May 2014 Senior Notes 7.625% Maturing in 2014 [Member]
Debt Instrument, Redemption [Line Items]
Debt instrument stated interest rate	7.625%
Extinguishment of debt	300
Securitization Bonds [Member] | Electric [Member] | March 2014 Securitization Bonds 6.62% Maturing in 2014 [Member]
Debt Instrument, Redemption [Line Items]
Debt instrument stated interest rate	6.62%
Extinguishment of debt	100
Securitization Bonds [Member] | Electric [Member] | September 2014 Securitization Bonds 6.62% Maturing in 2014 [Member]
Debt Instrument, Redemption [Line Items]
Debt instrument stated interest rate	6.62%
Extinguishment of debt	96
Tax Exempt Revenue Bonds [Member] | Electric [Member] | April 2014 Tax Exempt Revenue Bonds 2.35% Maturing in 2024 [Member]
Debt Instrument, Redemption [Line Items]
Debt instrument stated interest rate	2.35%
Extinguishment of debt	31
Tax Exempt Revenue Bonds [Member] | Electric [Member] | April 2014 Tax Exempt Revenue Bonds 4.65% Maturing in 2028 [Member]
Debt Instrument, Redemption [Line Items]
Debt instrument stated interest rate	4.65%
Extinguishment of debt	32
Tax Exempt Revenue Bonds [Member] | Electric [Member] | June 2014 Tax Exempt Revenue Bonds 4.875% Maturing in 2029 [Member]
Debt Instrument, Redemption [Line Items]
Debt instrument stated interest rate	4.875%
Extinguishment of debt	36
Tax Exempt Revenue Bonds [Member] | Electric [Member] | June 2014 Tax Exempt Revenue Bonds 6.00% Maturing in 2036 [Member]
Debt Instrument, Redemption [Line Items]
Debt instrument stated interest rate	6.00%
Extinguishment of debt	69
Tax Exempt Revenue Bonds [Member] | Electric [Member] | August 2014 Tax Exempt Revenue Bonds 5.25% Maturing in 2029 [Member]
Debt Instrument, Redemption [Line Items]
Debt instrument stated interest rate	5.25%
Extinguishment of debt	60
Long Term Debt, Other [Member] | DTE Energy [Member]
Debt Instrument, Redemption [Line Items]
Extinguishment of debt	$ 20