Income Taxes (Deferred Tax Assets (Liabilities)) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Components of Deferred Tax Assets and Liabilities [Abstract]
Property, plant, and equipment	$ (3,462)	$ (3,276)
Regulatory assets and liabilities	(54)	(94)
Tax credit carry-forwards	1,178	947
Pension and benefits	311	334
Federal net operating loss carry-forward	117	83
State and local net operating loss carry-forwards	59	70
Investments in equity method investees	(216)	(82)
Other	125	170
Deferred tax liabilities, gross	(1,942)	(1,848)
Less valuation allowance	(33)	(40)
Deferred income tax liabilities	(1,975)	(1,888)
Deferred income tax assets	2,021	1,814
Deferred income tax liabilities	(3,996)	(3,702)
DTE Electric
Components of Deferred Tax Assets and Liabilities [Abstract]
Property, plant, and equipment	(2,840)	(2,698)
Regulatory assets and liabilities	(3)	(31)
Tax credit carry-forwards	250	193
Pension and benefits	258	302
Federal net operating loss carry-forward	2	47
State and local net operating loss carry-forwards	1	5
Investments in equity method investees	(1)	0
Other	87	94
Deferred tax liabilities, gross	(2,246)	(2,088)
Less valuation allowance	0	0
Deferred income tax liabilities	(2,246)	(2,088)
Deferred income tax assets	855	830
Deferred income tax liabilities	$ (3,101)	$ (2,918)