Leases (Components of Lease Cost) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 19	$ 21	$ 23
Finance lease cost:
Amortization of right-of-use assets	7	5	4
Interest of lease liabilities	1	0	0
Total finance lease cost	8	5	4
Variable lease cost	9	10	10
Short-term lease cost	14	11	9
Total lease cost	50	47	46
DTE Electric
Lessee, Lease, Description [Line Items]
Operating lease cost	14	14	17
Finance lease cost:
Amortization of right-of-use assets	6	4	4
Interest of lease liabilities	0	0	0
Total finance lease cost	6	4	4
Variable lease cost	0	0	0
Short-term lease cost	6	6	3
Total lease cost	$ 26	$ 24	$ 24