Retirement Benefits and Trusteed Assets (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 27	$ 24	$ 54	$ 49
Interest cost	40	47	79	93
Expected return on plan assets	(86)	(83)	(170)	(166)
Amortization of net actuarial loss	49	43	98	86
Amortization of prior service credit	0	0	0	0
Net periodic benefit cost (credit)	30	31	61	62
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	7	7	15	13
Interest cost	12	14	23	28
Expected return on plan assets	(32)	(32)	(64)	(64)
Amortization of net actuarial loss	4	3	7	8
Amortization of prior service credit	(5)	(5)	(10)	(10)
Net periodic benefit cost (credit)	(14)	(13)	(29)	(25)
Other Postretirement Benefits | DTE Electric
Defined Benefit Plan Disclosure [Line Items]
Service cost	5	5	11	10
Interest cost	9	10	17	21
Expected return on plan assets	(21)	(22)	(43)	(44)
Amortization of net actuarial loss	3	3	6	6
Amortization of prior service credit	(4)	(3)	(7)	(7)
Net periodic benefit cost (credit)	$ (8)	$ (7)	$ (16)	$ (14)