Income Taxes (Deferred Tax Assets (Liabilities)) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Components of Deferred Tax Assets and Liabilities [Abstract]
Property, plant, and equipment	$ (4,211)	$ (3,832)
Securitized regulatory assets	5	(2)
Tax credit carry-forwards	465	296
Pension and benefits	(301)	(152)
Federal net operating loss carry-forward	177	0
State and local net operating loss carry-forwards	63	39
Investments in equity method investees	(82)	(84)
Other	(4)	65
Deferred Tax Liabilities, Gross	(3,888)	(3,670)
Less valuation allowance	(35)	(31)
Deferred income tax assets	1,088	861
Deferred income tax liabilities	(5,011)	(4,562)
Deferred income tax liabilities	(3,923)	(3,701)
DTE Electric
Components of Deferred Tax Assets and Liabilities [Abstract]
Property, plant, and equipment	(3,468)	(3,152)
Securitized regulatory assets	5	(3)
Tax credit carry-forwards	53	0
Pension and benefits	(193)	(43)
Federal net operating loss carry-forward	142	0
State and local net operating loss carry-forwards	16	0
Investments in equity method investees	0	0
Other	(53)	12
Deferred Tax Liabilities, Gross	(3,498)	(3,186)
Less valuation allowance	0	0
Deferred income tax assets	453	357
Deferred income tax liabilities	(3,951)	(3,543)
Deferred income tax liabilities	$ (3,498)	$ (3,186)