Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Tax effect on benefit obligation	$ 8	$ (9)	$ 13
Tax effect on net unrealized gains (losses) on investments during the period	0	1	1
DTE Electric
Benefit obligations	18	0	0
Tax effect on benefit obligation	0	(4)	4
Tax effect on net unrealized gains (losses) on investments during the period	$ 0	$ 0	$ 0