Financial and Other Derivative Instruments (Fair Value of Derivative Instruments) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 580	$ 775
Derivative Liabilities	(564)	(770)
Current derivative assets
Derivatives, Fair Value [Line Items]
Derivative Assets	444	646
Current derivative liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	(421)	(596)
Noncurrent derivative assets
Derivatives, Fair Value [Line Items]
Derivative Assets	136	129
Noncurrent derivative liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	(143)	(174)
Foreign currency exchange contracts
Derivatives, Fair Value [Line Items]
Derivative Assets	2	1
Derivative Liabilities	(2)	0
Natural gas
Derivatives, Fair Value [Line Items]
Derivative Assets	240	355
Derivative Liabilities	(265)	(351)
Electricity
Derivatives, Fair Value [Line Items]
Derivative Assets	137	306
Derivative Liabilities	(126)	(298)
Environmental & Other
Derivatives, Fair Value [Line Items]
Derivative Assets	201	113
Derivative Liabilities	(171)	(121)
Derivatives designated as hedging instruments | Foreign currency exchange contracts
Derivatives, Fair Value [Line Items]
Derivative Assets	0	0
Derivative Liabilities	(1)	0
Derivatives not designated as hedging instruments
Derivatives, Fair Value [Line Items]
Derivative Assets	580	775
Derivative Liabilities	(563)	(770)
Derivatives not designated as hedging instruments | DTE Electric
Derivatives, Fair Value [Line Items]
Derivative Assets	7	3
Derivatives not designated as hedging instruments | Foreign currency exchange contracts
Derivatives, Fair Value [Line Items]
Derivative Assets	2	1
Derivative Liabilities	(1)	0
Derivatives not designated as hedging instruments | Natural gas
Derivatives, Fair Value [Line Items]
Derivative Assets	240	355
Derivative Liabilities	(265)	(351)
Derivatives not designated as hedging instruments | Electricity
Derivatives, Fair Value [Line Items]
Derivative Assets	137	306
Derivative Liabilities	(126)	(298)
Derivatives not designated as hedging instruments | Environmental & Other
Derivatives, Fair Value [Line Items]
Derivative Assets	201	113
Derivative Liabilities	(171)	(121)
Derivatives not designated as hedging instruments | FTRs — Other current assets | DTE Electric
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 7	$ 3