New Accounting Pronouncements (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Jan. 01, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
True-up adjustment to the remeasurement of deferred taxes	$ 21
Regulatory Liabilities
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
True-up adjustment to the remeasurement of deferred taxes	17
DTE Electric
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
True-up adjustment to the remeasurement of deferred taxes	$ 7
Accounting Standards Update 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Implementation of ASU 2016-09		$ 0
Accounting Standards Update 2016-01 | DTE Electric
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Implementation of ASU 2016-09		0
Accumulated Other Comprehensive Income (Loss) | Accounting Standards Update 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Implementation of ASU 2016-09		(5)
Accumulated Other Comprehensive Income (Loss) | Accounting Standards Update 2016-01 | DTE Electric
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Implementation of ASU 2016-09		(3)
Retained Earnings | Accounting Standards Update 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Implementation of ASU 2016-09		5
Retained Earnings | Accounting Standards Update 2016-01 | DTE Electric
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Implementation of ASU 2016-09		$ 3