Retirement Benefits and Trusteed Assets (Pension Plan - Pension Cost Inclusions) (Details) - Pension plan - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	$ 92	$ 100	$ 83
Interest cost	219	210	212
Expected return on plan assets	(309)	(296)	(273)
Net actuarial loss	164	205	157
Prior service cost	1	0	0
Other	0	2	0
Net pension cost	167	221	179
DTE Electric
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	71	77	64
Interest cost	166	160	162
Expected return on plan assets	(220)	(210)	(194)
Net actuarial loss	118	147	110
Prior service cost	1	1	2
Other	0	1	0
Net pension cost	$ 136	$ 176	$ 144