Fair Value (Fair Value of Nuclear Decommissioning Trust Fund Assets) (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Nuclear decommissioning trust funds	$ 1,267	$ 1,241
DTE Electric
Schedule of Available-for-sale Securities [Line Items]
Nuclear decommissioning trust funds	1,267	1,241
DTE Electric | Fermi 2
Schedule of Available-for-sale Securities [Line Items]
Nuclear decommissioning trust funds	1,245	1,221
DTE Electric | Fermi 1
Schedule of Available-for-sale Securities [Line Items]
Nuclear decommissioning trust funds	3	3
DTE Electric | Low-level radioactive waste
Schedule of Available-for-sale Securities [Line Items]
Nuclear decommissioning trust funds	19	17
DTE Electric | Nuclear decommissioning trust fund
Schedule of Available-for-sale Securities [Line Items]
Nuclear decommissioning trust funds	$ 1,267	$ 1,241