Income Taxes (Reconciliation of Income Tax Expense to the Statutory Federal Income Tax Rate) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Income Before Income Taxes	$ 950	$ 1,275	$ 922
Income tax expense at 35% statutory rate	333	446	323
Production tax credits	(122)	(119)	(68)
Investment tax credits	(7)	(6)	(6)
Depreciation	(4)	(4)	(4)
AFUDC - Equity	(8)	(7)	(5)
Employee Stock Ownership Plan dividends	(5)	(4)	(4)
Domestic production activities deduction	0	0	(14)
State and local income taxes, net of federal benefit	35	51	37
Enactment of New York Corporate Income Tax Legislation, net of federal benefit	0	8	0
Other, net	8	(1)	(5)
Income Tax Expense (Benefit)	$ 230	$ 364	$ 254
Effective income tax rate (as percent)	24.20%	28.50%	27.50%
DTE Electric
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Income Before Income Taxes	$ 836	$ 830	$ 741
Income tax expense at 35% statutory rate	293	291	260
Production tax credits	(31)	(22)	(15)
Investment tax credits	(5)	(5)	(5)
Depreciation	3	3	3
AFUDC - Equity	(7)	(7)	(5)
Employee Stock Ownership Plan dividends	(3)	(3)	(2)
Domestic production activities deduction	0	(2)	(18)
State and local income taxes, net of federal benefit	43	43	41
Other, net	(1)	0	(5)
Income Tax Expense (Benefit)	$ 292	$ 298	$ 254
Effective income tax rate (as percent)	34.90%	35.90%	34.30%