Premises and Equipment and Other Assets - Rental, Depreciation, and Amortization Expenses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Rental, depreciation and amortization expenses
Depreciation and amortization of premises and equipment	$ 25	$ 26	$ 151
Premises and equipment
Rental, depreciation and amortization expenses
Rental expense of premises	128	134	120
Less: rental income	15	24	9
Net rental expense	113	110	111
Depreciation and amortization of premises and equipment	$ 92	$ 99	$ 105