Capital and Operating Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of Lessor Capital Leases [Line Items]
Rent expense	$ 51	$ 43	$ 43
Pipeline System Lease
Schedule of Lessor Capital Leases [Line Items]
Lessor capital lease renewal terms	5 years
Percent ownership in pipeline	40.00%
DTE Electric
Schedule of Lessor Capital Leases [Line Items]
Rent expense	$ 28	$ 28	$ 32