Retirement Benefits and Trusteed Assets (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 25	$ 21
Interest cost	46	55
Expected return on plan assets	(83)	(81)
Amortization of net actuarial loss	43	32
Amortization of prior service credit	0	0
Net periodic benefit cost (credit)	31	27
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	6	5
Interest cost	14	18
Expected return on plan assets	(32)	(31)
Amortization of net actuarial loss	5	3
Amortization of prior service credit	(5)	(2)
Net periodic benefit cost (credit)	(12)	(7)
Other Postretirement Benefits | DTE Electric
Defined Benefit Plan Disclosure [Line Items]
Service cost	5	4
Interest cost	11	13
Expected return on plan assets	(22)	(21)
Amortization of net actuarial loss	3	1
Amortization of prior service credit	(4)	(1)
Net periodic benefit cost (credit)	$ (7)	$ (4)