Financial and Other Derivative Instruments (Fair Value of Derivative Instruments) (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Derivative asset, gross	$ 607	$ 1,178
Derivative liability, gross	(601)	(1,110)
Natural Gas
Derivatives, Fair Value [Line Items]
Derivative asset, gross	251	787
Derivative liability, gross	(256)	(718)
Electricity
Derivatives, Fair Value [Line Items]
Derivative asset, gross	312	342
Derivative liability, gross	(305)	(342)
Other
Derivatives, Fair Value [Line Items]
Derivative asset, gross	37	45
Derivative liability, gross	(34)	(45)
Current derivative asset
Derivatives, Fair Value [Line Items]
Derivative asset, gross	506	1,083
Current derivative liability
Derivatives, Fair Value [Line Items]
Derivative liability, gross	(501)	(1,041)
Noncurrent derivative asset
Derivatives, Fair Value [Line Items]
Derivative asset, gross	101	95
Noncurrent derivative liability
Derivatives, Fair Value [Line Items]
Derivative liability, gross	(100)	(69)
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Derivative asset, gross	607	1,178
Derivative liability, gross	(601)	(1,110)
Not Designated as Hedging Instrument | DTE Electric
Derivatives, Fair Value [Line Items]
Derivative asset, gross	5	3
Not Designated as Hedging Instrument | Foreign currency exchange contracts
Derivatives, Fair Value [Line Items]
Derivative asset, gross	7	4
Derivative liability, gross	(6)	(5)
Not Designated as Hedging Instrument | Natural Gas
Derivatives, Fair Value [Line Items]
Derivative asset, gross	251	787
Derivative liability, gross	(256)	(718)
Not Designated as Hedging Instrument | Electricity
Derivatives, Fair Value [Line Items]
Derivative asset, gross	312	342
Derivative liability, gross	(305)	(342)
Not Designated as Hedging Instrument | Other
Derivatives, Fair Value [Line Items]
Derivative asset, gross	37	45
Derivative liability, gross	(34)	(45)
Not Designated as Hedging Instrument | Financial transmission rights | DTE Electric
Derivatives, Fair Value [Line Items]
Derivative asset, gross	$ 5	$ 3