Capital and Operating Leases (Details Textuals) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Lessor Capital Leases [Line Items]
Rent expense	$ 43	$ 38	$ 34
DTE Electric
Schedule of Lessor Capital Leases [Line Items]
Rent expense	$ 32	$ 26	$ 28
Pipeline System Lease
Schedule of Lessor Capital Leases [Line Items]
Lessor capital lease renewal terms	5 years
Percent ownership in pipeline	40.00%
Minimum | Energy Services Agreement
Schedule of Lessor Capital Leases [Line Items]
Lessor capital lease renewal terms	3 years
Maximum | Energy Services Agreement
Schedule of Lessor Capital Leases [Line Items]
Lessor capital lease renewal terms	5 years