Income Taxes (Reconciliation of Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits, beginning balance	$ 3	$ 9	$ 10
Additions for tax positions of prior years	7	0	0
Lapse of statute of limitations	0	(6)	(1)
Unrecognized tax benefits, ending balance	10	3	9
DTE Electric
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits, beginning balance	4	4	4
Additions for tax positions of prior years	9	0	0
Unrecognized tax benefits, ending balance	$ 13	$ 4	$ 4