Retirement Benefits and Trusteed Assets (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 25	$ 21	$ 74	$ 63
Interest cost	46	55	139	164
Expected return on plan assets	(84)	(82)	(250)	(244)
Amortization of net actuarial loss	43	33	129	99
Amortization of prior service credit	0	0	0	0
Settlements	2	0	2	0
Net periodic benefit cost (credit)	32	27	94	82
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	7	5	20	16
Interest cost	14	18	42	53
Expected return on plan assets	(32)	(30)	(96)	(92)
Amortization of net actuarial loss	4	3	12	9
Amortization of prior service credit	(5)	(3)	(15)	(7)
Settlements	0	0	0	0
Net periodic benefit cost (credit)	(12)	(7)	(37)	(21)
Other Postretirement Benefits | DTE Electric
Defined Benefit Plan Disclosure [Line Items]
Service cost	5	4	15	12
Interest cost	11	13	32	40
Expected return on plan assets	(21)	(21)	(65)	(63)
Amortization of net actuarial loss	2	1	8	3
Amortization of prior service credit	(3)	(1)	(10)	(5)
Net periodic benefit cost (credit)	$ (6)	$ (4)	$ (20)	$ (13)