Retirement Benefits and Trusteed Assets (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 21	$ 25
Interest cost	55	50
Expected return on plan assets	(81)	(82)
Amortization of net actuarial loss	32	44
Amortization of prior service credit	0	0
Net periodic benefit cost (credit)	27	37
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	5	7
Interest cost	18	17
Expected return on plan assets	(31)	(36)
Amortization of net actuarial loss	3	3
Amortization of prior service credit	(2)	0
Net periodic benefit cost (credit)	(7)	(9)
Other Postretirement Benefits | DTE Electric
Defined Benefit Plan Disclosure [Line Items]
Service cost	4	5
Interest cost	13	13
Expected return on plan assets	(21)	(24)
Amortization of net actuarial loss	1	2
Amortization of prior service credit	(1)	0
Net periodic benefit cost (credit)	$ (4)	$ (4)