Certain Transfers of Financial Assets and Variable Interest Entities Community Development Tax Credits and Amortization (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Affordable Housing Tax Credits and Other Tax Benefits, Amount		$ 121	$ 108	$ 92
Amortization Method Qualified Affordable Housing Project Investments, Amortization		127	109	87
Amortization of Intangible Assets	[1]	18	20
Variable Interest Entity, Not Primary Beneficiary [Member]
Investment Tax Credit		89	90	64
Amortization of Intangible Assets		$ 71	$ 70	$ 46

[1] Does not include expense associated with community development investments. See Note 12, “Certain Transfers of Financial Assets and Variable Interest Entities,” for additional information.