Retirement Benefits and Trusteed Assets (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 23	$ 24	$ 46	$ 49
Interest cost	55	53	109	106
Expected return on plan assets	(78)	(74)	(155)	(148)
Amortization of net actuarial loss	41	52	81	103
Amortization of prior service cost (credit)	0	0	0	0
Net periodic benefit cost (credit)	41	55	81	110
Pension Benefits | DTE Electric
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	17	18	35	38
Interest cost	42	41	83	81
Expected return on plan assets	(55)	(52)	(110)	(105)
Amortization of net actuarial loss	28	36	57	74
Amortization of prior service cost (credit)	1	1	1	1
Net periodic benefit cost (credit)	33	44	66	89
Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	7	8	13	17
Interest cost	20	21	40	41
Expected return on plan assets	(32)	(32)	(64)	(65)
Amortization of net actuarial loss	8	11	16	22
Amortization of prior service cost (credit)	(29)	(32)	(59)	(63)
Net periodic benefit cost (credit)	(26)	(24)	(54)	(48)
Other Postretirement Benefits | DTE Electric
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	5	6	10	13
Interest cost	16	15	31	31
Expected return on plan assets	(22)	(22)	(45)	(45)
Amortization of net actuarial loss	5	8	11	16
Amortization of prior service cost (credit)	(22)	(23)	(44)	(47)
Net periodic benefit cost (credit)	$ (18)	$ (16)	$ (37)	$ (32)