Certain Transfers of Financial Assets and Variable Interest Entities Community Development Tax Credits and Amortization (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Affordable Housing Tax Credits and Other Tax Benefits, Amount		$ 32	$ 29	$ 65	$ 59
Amortization Method Qualified Affordable Housing Project Investments, Amortization		34	31	69	63
Investment Tax Credit			20
Amortization of Intangible Assets	[1]			7	11
Variable Interest Entity, Not Primary Beneficiary [Member]
Investment Tax Credit				38	38
Amortization of Intangible Assets		17	$ 16	$ 32	$ 31
Community Development Investments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Investment Tax Credit		$ 20

[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.