Retirement Benefits and Trusteed Assets (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 21	$ 24	$ 63	$ 74
Interest cost	55	51	164	151
Expected return on plan assets	(82)	(82)	(244)	(247)
Amortization of net actuarial loss	33	43	99	132
Amortization of prior service credit	0	0	0	0
Net periodic benefit cost (credit)	27	36	82	110
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	5	6	16	20
Interest cost	18	18	53	52
Expected return on plan assets	(30)	(36)	(92)	(107)
Amortization of net actuarial loss	3	3	9	8
Amortization of prior service credit	(3)	0	(7)	0
Net periodic benefit cost (credit)	(7)	(9)	(21)	(27)
Other Postretirement Benefits | DTE Electric
Defined Benefit Plan Disclosure [Line Items]
Service cost	4	5	12	15
Interest cost	13	13	40	40
Expected return on plan assets	(21)	(25)	(63)	(74)
Amortization of net actuarial loss	1	3	3	7
Amortization of prior service credit	(1)	0	(5)	0
Net periodic benefit cost (credit)	$ (4)	$ (4)	$ (13)	$ (12)