Financial and Other Derivative Instruments (Fair Value of Derivative Instruments) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 652	$ 549
Derivative Liabilities	(657)	(656)
Natural Gas
Derivatives, Fair Value [Line Items]
Derivative Assets	357	348
Derivative Liabilities	(378)	(461)
Electricity
Derivatives, Fair Value [Line Items]
Derivative Assets	285	193
Derivative Liabilities	(275)	(189)
Other
Derivatives, Fair Value [Line Items]
Derivative Assets	9	2
Derivative Liabilities	(1)	(3)
Foreign currency exchange contracts
Derivatives, Fair Value [Line Items]
Derivative Assets	1	6
Derivative Liabilities	(3)	(3)
Not designated as hedging instruments
Derivatives, Fair Value [Line Items]
Derivative Assets	652	549
Derivative Liabilities	(657)	(656)
Not designated as hedging instruments | Natural Gas
Derivatives, Fair Value [Line Items]
Derivative Assets	357	348
Derivative Liabilities	(378)	(461)
Not designated as hedging instruments | Electricity
Derivatives, Fair Value [Line Items]
Derivative Assets	285	193
Derivative Liabilities	(275)	(189)
Not designated as hedging instruments | Other
Derivatives, Fair Value [Line Items]
Derivative Assets	9	2
Derivative Liabilities	(1)	(3)
Not designated as hedging instruments | Foreign currency exchange contracts
Derivatives, Fair Value [Line Items]
Derivative Assets	1	6
Derivative Liabilities	(3)	(3)
Current derivative asset
Derivatives, Fair Value [Line Items]
Derivative Assets	540	447
Noncurrent derivative asset
Derivatives, Fair Value [Line Items]
Derivative Assets	112	102
Current derivative liability
Derivatives, Fair Value [Line Items]
Derivative Liabilities	(558)	(493)
Noncurrent derivative liability
Derivatives, Fair Value [Line Items]
Derivative Liabilities	(99)	(163)
DTE Electric | Not designated as hedging instruments
Derivatives, Fair Value [Line Items]
Derivative Assets	9	2
DTE Electric | Not designated as hedging instruments | FTRs — Other current assets
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 9	$ 2