Retirement Benefits and Trusteed Assets (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 27	$ 25	$ 81	$ 74
Interest cost	39	46	118	139
Expected return on plan assets	(84)	(84)	(254)	(250)
Amortization of net actuarial loss	49	43	147	129
Amortization of prior service credit	0	0	0	0
Settlements	0	2	0	2
Net periodic benefit cost (credit)	31	32	92	94
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	8	7	23	20
Interest cost	12	14	35	42
Expected return on plan assets	(33)	(32)	(97)	(96)
Amortization of net actuarial loss	3	4	10	12
Amortization of prior service credit	(5)	(5)	(15)	(15)
Settlements	0	0	0	0
Net periodic benefit cost (credit)	(15)	(12)	(44)	(37)
Other Postretirement Benefits | DTE Electric
Defined Benefit Plan Disclosure [Line Items]
Service cost	6	5	17	15
Interest cost	8	11	25	32
Expected return on plan assets	(22)	(21)	(65)	(65)
Amortization of net actuarial loss	3	2	9	8
Amortization of prior service credit	(3)	(3)	(10)	(10)
Net periodic benefit cost (credit)	$ (8)	$ (6)	$ (24)	$ (20)