Fair Value (Gains and Losses and Proceeds from the Sale of Securities by the Nuclear Decommissioning Trust Funds) (Details) - DTE Electric - Nuclear decommissioning trusts - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Realized gains	$ 83	$ 74	$ 39
Realized losses	(29)	(63)	(33)
Proceeds from sale of securities	$ 1,240	$ 1,457	$ 885