Retirement Benefits and Trusteed Assets (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 21	$ 25	$ 42	$ 50
Interest cost	54	50	109	100
Expected return on plan assets	(81)	(83)	(162)	(165)
Amortization of net actuarial loss	34	45	66	89
Amortization of prior service credit	0	0	0	0
Net periodic benefit cost (credit)	28	37	55	74
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	6	7	11	14
Interest cost	17	17	35	34
Expected return on plan assets	(31)	(35)	(62)	(71)
Amortization of net actuarial loss	3	2	6	5
Amortization of prior service credit	(2)	0	(4)	0
Net periodic benefit cost (credit)	(7)	(9)	(14)	(18)
Other Postretirement Benefits | DTE Electric
Defined Benefit Plan Disclosure [Line Items]
Service cost	4	5	8	10
Interest cost	14	14	27	27
Expected return on plan assets	(21)	(25)	(42)	(49)
Amortization of net actuarial loss	1	2	2	4
Amortization of prior service credit	(3)	0	(4)	0
Net periodic benefit cost (credit)	$ (5)	$ (4)	$ (9)	$ (8)