Financial and Other Derivative Instruments (Fair Value of Derivative Instruments) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 429	$ 663
Derivative Liabilities	(460)	(669)
Current derivative assets
Derivatives, Fair Value [Line Items]
Derivative Assets	346	563
Current derivative liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	(339)	(518)
Noncurrent derivative assets
Derivatives, Fair Value [Line Items]
Derivative Assets	83	100
Noncurrent derivative liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	(121)	(151)
Interest rate contracts
Derivatives, Fair Value [Line Items]
Derivative Liabilities	0	(3)
Natural gas
Derivatives, Fair Value [Line Items]
Derivative Assets	253	349
Derivative Liabilities	(297)	(380)
Electricity
Derivatives, Fair Value [Line Items]
Derivative Assets	164	303
Derivative Liabilities	(155)	(285)
Other
Derivatives, Fair Value [Line Items]
Derivative Assets	10	7
Derivative Liabilities	(8)	(1)
Foreign currency exchange contracts
Derivatives, Fair Value [Line Items]
Derivative Assets	2	4
Derivatives designated as hedging instruments | Interest rate contracts
Derivatives, Fair Value [Line Items]
Derivative Assets	0	0
Derivative Liabilities	0	(3)
Derivatives not designated as hedging instruments
Derivatives, Fair Value [Line Items]
Derivative Assets	429	663
Derivative Liabilities	(460)	(666)
Derivatives not designated as hedging instruments | DTE Electric
Derivatives, Fair Value [Line Items]
Derivative Assets	5	6
Derivatives not designated as hedging instruments | Natural gas
Derivatives, Fair Value [Line Items]
Derivative Assets	253	349
Derivative Liabilities	(297)	(380)
Derivatives not designated as hedging instruments | Electricity
Derivatives, Fair Value [Line Items]
Derivative Assets	164	303
Derivative Liabilities	(155)	(285)
Derivatives not designated as hedging instruments | Other
Derivatives, Fair Value [Line Items]
Derivative Assets	10	7
Derivative Liabilities	(8)	(1)
Derivatives not designated as hedging instruments | Foreign currency exchange contracts
Derivatives, Fair Value [Line Items]
Derivative Assets	2	4
Derivative Liabilities	0	0
Derivatives not designated as hedging instruments | FTRs — Other current assets | DTE Electric
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 5	$ 6