Certain Transfers of Financial Assets and Variable Interest Entities Community Development Tax Credits and Amortization (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Affordable Housing Tax Credits and Other Tax Benefits, Amount		$ 33	$ 28	$ 98	$ 87
Amortization Method Qualified Affordable Housing Project Investments, Amortization		35	29	103	92
Amortization of Intangible Assets	[1]			9	13
Variable Interest Entity, Not Primary Beneficiary [Member]
Investment Tax Credit		25	23	64	62
Amortization of Intangible Assets		$ 21	$ 19	$ 53	$ 49

[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.