Significant Accounting Policies (Intangible Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	$ 912	$ 151
Accumulated Amortization	(70)	(62)
Intangible assets, net carrying value	$ 842	89
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Useful Lives	40 years
DTE Energy
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	$ 881	117
Accumulated Amortization	(70)	(62)
Finite-lived intangible assets, net carrying value	811	55
DTE Energy | Customer relationships
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	770	0
Accumulated Amortization	(5)	0
Finite-lived intangible assets, net carrying value	765	0
DTE Energy | Contract intangibles
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	111	117
Accumulated Amortization	(65)	(62)
Finite-lived intangible assets, net carrying value	46	55
DTE Electric
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	31	39
Intangible assets, gross	31	34
Accumulated Amortization	0	0
Less current DTE Electric intangible assets	0	5
Intangible assets, net carrying value	31	34
DTE Electric | DTE Electric renewable energy credits
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	30	38
DTE Electric | DTE Electric emission allowances
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	$ 1	$ 1
Minimum | Contract intangibles
Finite-Lived Intangible Assets [Line Items]
Useful Lives	6 years
Maximum | Contract intangibles
Finite-Lived Intangible Assets [Line Items]
Useful Lives	26 years