Retirement Benefits and Trusteed Assets (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 27	$ 25
Interest cost	39	46
Expected return on plan assets	(84)	(83)
Amortization of net actuarial loss	49	43
Amortization of prior service credit	0	0
Net periodic benefit cost (credit)	31	31
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	8	6
Interest cost	11	14
Expected return on plan assets	(32)	(32)
Amortization of net actuarial loss	3	5
Amortization of prior service credit	(5)	(5)
Net periodic benefit cost (credit)	(15)	(12)
Other Postretirement Benefits | DTE Electric
Defined Benefit Plan Disclosure [Line Items]
Service cost	6	5
Interest cost	8	11
Expected return on plan assets	(22)	(22)
Amortization of net actuarial loss	3	3
Amortization of prior service credit	(3)	(4)
Net periodic benefit cost (credit)	$ (8)	$ (7)