Income Taxes (Components of Income Tax Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current income tax expense (benefit)
Federal	$ (22)	$ (1)	$ (3)
State and other income tax	1	7	(4)
Total current income taxes	(21)	6	(7)
Deferred income tax expense
Federal	118	184	178
State and other income tax	78	81	59
Total deferred income taxes	196	265	237
Total	175	271	230
DTE Electric
Current income tax expense (benefit)
Federal	(17)	0	(26)
State and other income tax	(1)	11	(2)
Total current income taxes	(18)	11	(28)
Deferred income tax expense
Federal	270	268	252
State and other income tax	75	74	68
Total deferred income taxes	345	342	320
Total	$ 327	$ 353	$ 292