Certain Transfers of Financial Assets and Variable Interest Entities Community Development Tax Credits and Amortization (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Affordable Housing Tax Credits and Other Tax Benefits, Amount		$ 33	$ 30
Amortization Method Qualified Affordable Housing Project Investments, Amortization		35	32
Amortization of Intangible Assets	[1]	3	5
Variable Interest Entity, Not Primary Beneficiary [Member]
Investment Tax Credit		18	18
Amortization of Intangible Assets		$ 15	$ 14

[1] Does not include expense associated with community development investments. See Note 11, “Certain Transfers of Financial Assets and Variable Interest Entities,” for additional information.