Variable Interest Entities - Unconsolidated LIHC Investments (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Other Non Interest Expenses
Noncontrolling Interest [Line Items]
Losses from LIHC investments included in other noninterest expense	$ 1	$ 2	$ 3	$ 5
Income Tax Expense
Noncontrolling Interest [Line Items]
Amortization of LIHC investments included in income tax expense	32	33	91	97
Tax credits and other tax benefits from LIHC investments included in income tax expense	$ 38	$ 44	$ 117	$ 130