Financial and Other Derivative Instruments (Fair Value of Derivative Instruments) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Derivative asset, gross	$ 586	$ 1,178
Derivative liability, gross	(551)	(1,110)
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative asset, gross	586	1,178
Derivative liability, gross	(551)	(1,110)
DTE Electric | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative asset, gross	5	3
Foreign currency exchange contracts | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative asset, gross	10	4
Derivative liability, gross	(7)	(5)
Natural Gas
Derivatives, Fair Value [Line Items]
Derivative asset, gross	303	787
Derivative liability, gross	(277)	(718)
Natural Gas | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative asset, gross	303	787
Derivative liability, gross	(277)	(718)
Electricity
Derivatives, Fair Value [Line Items]
Derivative asset, gross	251	342
Derivative liability, gross	(244)	(342)
Electricity | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative asset, gross	251	342
Derivative liability, gross	(244)	(342)
Other
Derivatives, Fair Value [Line Items]
Derivative asset, gross	22	45
Derivative liability, gross	(23)	(45)
Other | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative asset, gross	22	45
Derivative liability, gross	(23)	(45)
Financial transmission rights | DTE Electric | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative asset, gross	5	3
Current derivative asset
Derivatives, Fair Value [Line Items]
Derivative asset, gross	448	1,083
Current derivative liability
Derivatives, Fair Value [Line Items]
Derivative liability, gross	(419)	(1,041)
Noncurrent derivative asset
Derivatives, Fair Value [Line Items]
Derivative asset, gross	138	95
Noncurrent derivative liability
Derivatives, Fair Value [Line Items]
Derivative liability, gross	$ (132)	$ (69)