Leases (Other Information) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($)
Cash paid for amounts included in the measurement of these liabilities:
Operating cash flows for finance leases	$ 5
Operating cash flows for operating leases	40
Right-of-use assets obtained in exchange for lease obligations:
Operating leases	68
Finance leases	$ 8
Weighted Average Remaining Lease Term
Operating leases	9 years 8 months 12 days
Finance leases	9 years 1 month 6 days
Weighted Average Discount Rate
Operating leases	3.50%
Finance leases	3.10%
DTE Electric
Cash paid for amounts included in the measurement of these liabilities:
Operating cash flows for finance leases	$ 5
Operating cash flows for operating leases	16
Right-of-use assets obtained in exchange for lease obligations:
Operating leases	27
Finance leases	$ 0
Weighted Average Remaining Lease Term
Operating leases	10 years 7 months 6 days
Finance leases	2 years
Weighted Average Discount Rate
Operating leases	3.30%
Finance leases	3.10%