Financial and Other Derivative Instruments (Fair Value of Derivative Instruments) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 567	$ 775
Derivative Liabilities	(533)	(770)
Current derivative asset
Derivatives, Fair Value [Line Items]
Derivative Assets	446	646
Noncurrent derivative asset
Derivatives, Fair Value [Line Items]
Derivative Assets	121	129
Current derivative liability
Derivatives, Fair Value [Line Items]
Derivative Liabilities	(386)	(596)
Noncurrent derivative liability
Derivatives, Fair Value [Line Items]
Derivative Liabilities	(147)	(174)
Foreign currency exchange contracts
Derivatives, Fair Value [Line Items]
Derivative Assets	0	1
Derivative Liabilities	(5)	0
Natural gas
Derivatives, Fair Value [Line Items]
Derivative Assets	233	355
Derivative Liabilities	(223)	(351)
Electricity
Derivatives, Fair Value [Line Items]
Derivative Assets	180	306
Derivative Liabilities	(168)	(298)
Environmental & Other
Derivatives, Fair Value [Line Items]
Derivative Assets	154	113
Derivative Liabilities	(137)	(121)
Derivatives designated as hedging instruments | Foreign currency exchange contracts
Derivatives, Fair Value [Line Items]
Derivative Assets	0	0
Derivative Liabilities	(4)	0
Derivatives not designated as hedging instruments
Derivatives, Fair Value [Line Items]
Derivative Assets	567	775
Derivative Liabilities	(529)	(770)
Derivatives not designated as hedging instruments | DTE Electric
Derivatives, Fair Value [Line Items]
Derivative Assets	4	3
Derivatives not designated as hedging instruments | Foreign currency exchange contracts
Derivatives, Fair Value [Line Items]
Derivative Assets	0	1
Derivative Liabilities	(1)	0
Derivatives not designated as hedging instruments | Natural gas
Derivatives, Fair Value [Line Items]
Derivative Assets	233	355
Derivative Liabilities	(223)	(351)
Derivatives not designated as hedging instruments | Electricity
Derivatives, Fair Value [Line Items]
Derivative Assets	180	306
Derivative Liabilities	(168)	(298)
Derivatives not designated as hedging instruments | Environmental & Other
Derivatives, Fair Value [Line Items]
Derivative Assets	154	113
Derivative Liabilities	(137)	(121)
Derivatives not designated as hedging instruments | FTRs — Other current assets | DTE Electric
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 4	$ 3