Financial and Other Derivative Instruments (Fair Value of Derivative Instruments) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 2,340	$ 567
Derivative Liabilities	(2,557)	(533)
Current derivative assets
Derivatives, Fair Value [Line Items]
Derivative Assets	1,938	446
Current derivative liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	(2,011)	(386)
Noncurrent derivative assets
Derivatives, Fair Value [Line Items]
Derivative Assets	402	121
Noncurrent derivative liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	(546)	(147)
Foreign currency exchange contracts
Derivatives, Fair Value [Line Items]
Derivative Liabilities	(5)	(5)
Natural gas
Derivatives, Fair Value [Line Items]
Derivative Assets	778	233
Derivative Liabilities	(1,055)	(223)
Electricity
Derivatives, Fair Value [Line Items]
Derivative Assets	952	180
Derivative Liabilities	(916)	(168)
Environmental & Other
Derivatives, Fair Value [Line Items]
Derivative Assets	610	154
Derivative Liabilities	(581)	(137)
Derivatives designated as hedging instruments | Foreign currency exchange contracts
Derivatives, Fair Value [Line Items]
Derivative Assets	0	0
Derivative Liabilities	(3)	(4)
Derivatives not designated as hedging instruments
Derivatives, Fair Value [Line Items]
Derivative Assets	2,340	567
Derivative Liabilities	(2,554)	(529)
Derivatives not designated as hedging instruments | DTE Electric
Derivatives, Fair Value [Line Items]
Derivative Assets	12	4
Derivatives not designated as hedging instruments | Foreign currency exchange contracts
Derivatives, Fair Value [Line Items]
Derivative Assets	0	0
Derivative Liabilities	(2)	(1)
Derivatives not designated as hedging instruments | Natural gas
Derivatives, Fair Value [Line Items]
Derivative Assets	778	233
Derivative Liabilities	(1,055)	(223)
Derivatives not designated as hedging instruments | Electricity
Derivatives, Fair Value [Line Items]
Derivative Assets	952	180
Derivative Liabilities	(916)	(168)
Derivatives not designated as hedging instruments | Environmental & Other
Derivatives, Fair Value [Line Items]
Derivative Assets	610	154
Derivative Liabilities	(581)	(137)
Derivatives not designated as hedging instruments | FTRs — Other current assets | DTE Electric
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 12	$ 4