Variable Interest Entities - Unconsolidated LIHC Investments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Other Non Interest Expenses
Noncontrolling Interest [Line Items]
Losses from LIHC investments included in other noninterest expense	$ 2	$ 2
Income Tax Expense
Noncontrolling Interest [Line Items]
Amortization of LIHC investments included in income tax expense	34	34
Tax credits and other tax benefits from LIHC investments included in income tax expense	$ 45	$ 44