Financial and Other Derivative Instruments (Fair Value of Derivative Instruments) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Derivative asset, gross	$ 764	$ 1,178
Derivative liability, gross	(770)	(1,110)
Natural Gas
Derivatives, Fair Value [Line Items]
Derivative asset, gross	443	787
Derivative liability, gross	(455)	(718)
Electricity
Derivatives, Fair Value [Line Items]
Derivative asset, gross	270	342
Derivative liability, gross	(262)	(342)
Other
Derivatives, Fair Value [Line Items]
Derivative asset, gross	43	45
Derivative liability, gross	(46)	(45)
Current derivative asset
Derivatives, Fair Value [Line Items]
Derivative asset, gross	676	1,083
Current derivative liability
Derivatives, Fair Value [Line Items]
Derivative liability, gross	(680)	(1,041)
Noncurrent derivative asset
Derivatives, Fair Value [Line Items]
Derivative asset, gross	88	95
Noncurrent derivative liability
Derivatives, Fair Value [Line Items]
Derivative liability, gross	(90)	(69)
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative asset, gross	764	1,178
Derivative liability, gross	(770)	(1,110)
Not Designated as Hedging Instrument | DTE Electric
Derivatives, Fair Value [Line Items]
Derivative asset, gross	1	3
Not Designated as Hedging Instrument | Foreign currency exchange contracts
Derivatives, Fair Value [Line Items]
Derivative asset, gross	8	4
Derivative liability, gross	(7)	(5)
Not Designated as Hedging Instrument | Natural Gas
Derivatives, Fair Value [Line Items]
Derivative asset, gross	443	787
Derivative liability, gross	(455)	(718)
Not Designated as Hedging Instrument | Electricity
Derivatives, Fair Value [Line Items]
Derivative asset, gross	270	342
Derivative liability, gross	(262)	(342)
Not Designated as Hedging Instrument | Other
Derivatives, Fair Value [Line Items]
Derivative asset, gross	43	45
Derivative liability, gross	(46)	(45)
Not Designated as Hedging Instrument | Financial transmission rights | DTE Electric
Derivatives, Fair Value [Line Items]
Derivative asset, gross	$ 1	$ 3