Variable Interest Entities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Variable Interest Entity [Line Items]
Loans held for investment	$ 88,213	$ 86,507
Non Interest Expenses
Variable Interest Entity [Line Items]
Losses from LIHC investments included in other noninterest expense	(6)	(7)	$ (13)
Income Tax Expense
Variable Interest Entity [Line Items]
Amortization of LIHC investments included in income tax expense	130	136	185
Tax credits and other tax benefits from LIHC investments included in income tax expense	178	180	$ 193
Unconsolidated VIEs
Variable Interest Entity [Line Items]
Loans held for investment	232	217
Unconsolidated VIEs | LIHC investments
Variable Interest Entity [Line Items]
Loans held for investment	219	198
Unconsolidated VIEs | Leasing investments
Variable Interest Entity [Line Items]
Loans held for investment	0	19
Unconsolidated VIEs | Other investments
Variable Interest Entity [Line Items]
Loans held for investment	$ 13	$ 0