Long-Term Debt (Debt Issuances) (Details)	Dec. 31, 2015 USD ($)
Debt Instrument [Line Items]
Amount	$ 965,000,000
DTE Electric | Mortgage Bonds | March 3.70% 2045
Debt Instrument [Line Items]
Interest Rate	3.70%
Amount	$ 500,000,000
DTE Energy | Senior Notes | June 3.30% 2022
Debt Instrument [Line Items]
Interest Rate	3.30%
Amount	$ 300,000,000
DTE Gas | Mortgage Bonds | August 3.35% 2027
Debt Instrument [Line Items]
Interest Rate	3.35%
Amount	$ 40,000,000
DTE Gas | Mortgage Bonds | August 4.21% 2045
Debt Instrument [Line Items]
Interest Rate	4.21%
Amount	$ 125,000,000