Financial and Other Derivative Instruments (Fair Value of Derivative Instruments) (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 442	$ 652
Derivative Liabilities	(458)	(657)
Current derivative assets
Derivatives, Fair Value [Line Items]
Derivative Assets	361	540
Current derivative liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	(342)	(558)
Noncurrent derivative assets
Derivatives, Fair Value [Line Items]
Derivative Assets	81	112
Noncurrent derivative liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	(116)	(99)
Natural gas
Derivatives, Fair Value [Line Items]
Derivative Assets	200	357
Derivative Liabilities	(229)	(378)
Electricity
Derivatives, Fair Value [Line Items]
Derivative Assets	234	285
Derivative Liabilities	(227)	(275)
Other
Derivatives, Fair Value [Line Items]
Derivative Assets	7	9
Derivative Liabilities	(1)	(1)
Foreign currency exchange contracts
Derivatives, Fair Value [Line Items]
Derivative Assets	1	1
Derivative Liabilities	(1)	(3)
Derivatives not designated as hedging instruments
Derivatives, Fair Value [Line Items]
Derivative Assets	442	652
Derivative Liabilities	(458)	(657)
Derivatives not designated as hedging instruments | DTE Electric
Derivatives, Fair Value [Line Items]
Derivative Assets	6	9
Derivatives not designated as hedging instruments | Natural gas
Derivatives, Fair Value [Line Items]
Derivative Assets	200	357
Derivative Liabilities	(229)	(378)
Derivatives not designated as hedging instruments | Electricity
Derivatives, Fair Value [Line Items]
Derivative Assets	234	285
Derivative Liabilities	(227)	(275)
Derivatives not designated as hedging instruments | Other
Derivatives, Fair Value [Line Items]
Derivative Assets	7	9
Derivative Liabilities	(1)	(1)
Derivatives not designated as hedging instruments | Foreign currency exchange contracts
Derivatives, Fair Value [Line Items]
Derivative Assets	1	1
Derivative Liabilities	(1)	(3)
Derivatives not designated as hedging instruments | FTRs — Other current assets | DTE Electric
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 6	$ 9