Income Taxes (Deferred Tax Assets (Liabilities)) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Components of Deferred Tax Assets and Liabilities [Abstract]
Property, plant, and equipment	$ (3,276)	$ (4,880)
Regulatory assets and liabilities	(94)	(879)
Tax credit carry-forwards	947	643
Pension and benefits	334	643
Federal net operating loss carry-forward	83	190
State and local net operating loss carry-forwards	70	59
Investments in equity method investees	(82)	(119)
Other	170	217
Deferred tax liabilities, gross	(1,848)	(4,126)
Less valuation allowance	(40)	(36)
Deferred income tax liabilities	(1,888)	(4,162)
Deferred income tax assets	1,814	1,463
Deferred income tax liabilities	(3,702)	(5,625)
DTE Electric
Components of Deferred Tax Assets and Liabilities [Abstract]
Property, plant, and equipment	(2,698)	(3,819)
Regulatory assets and liabilities	(31)	(778)
Tax credit carry-forwards	193	116
Pension and benefits	302	518
Federal net operating loss carry-forward	47	42
State and local net operating loss carry-forwards	5	1
Investments in equity method investees	0	0
Other	94	127
Deferred tax liabilities, gross	(2,088)	(3,793)
Less valuation allowance	0	0
Deferred income tax liabilities	(2,088)	(3,793)
Deferred income tax assets	830	569
Deferred income tax liabilities	$ (2,918)	$ (4,362)