Retirement Benefits and Trusteed Assets (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 23	$ 23	$ 47	$ 46
Interest cost	53	55	107	109
Expected return on plan assets	(77)	(78)	(155)	(155)
Amortization of net actuarial loss	43	41	86	81
Amortization of prior service cost (credit)	0	0	0	0
Net periodic benefit cost (credit)	42	41	85	81
Pension Benefits | DTE Electric
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	19	17	37	35
Interest cost	40	42	81	83
Expected return on plan assets	(56)	(55)	(111)	(110)
Amortization of net actuarial loss	31	28	62	57
Amortization of prior service cost (credit)	0	1	0	1
Net periodic benefit cost (credit)	34	33	69	66
Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	6	7	13	13
Interest cost	19	20	37	40
Expected return on plan assets	(32)	(32)	(65)	(64)
Amortization of net actuarial loss	4	8	7	16
Amortization of prior service cost (credit)	(4)	(29)	(7)	(59)
Net periodic benefit cost (credit)	(7)	(26)	(15)	(54)
Other Postretirement Benefits | DTE Electric
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	5	5	10	10
Interest cost	14	16	28	31
Expected return on plan assets	(22)	(22)	(45)	(45)
Amortization of net actuarial loss	2	5	4	11
Amortization of prior service cost (credit)	(3)	(22)	(5)	(44)
Net periodic benefit cost (credit)	$ (4)	$ (18)	$ (8)	$ (37)