Deposits and Borrowings - Schedule of Components of Interest Expense on Short-Term Borrowings and Long-Term Debt (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Short-term borrowings:
Federal funds purchased and securities loaned or sold under agreements to repurchase	$ 1	$ 2	$ 1
FHLB advances	9	19	28
Total short-term borrowings	10	21	29
Long-term debt:
Securitized debt obligations	151	145	183
Senior and subordinated notes	330	299	315
Other long-term borrowings	43	26	24
Total long-term debt	524	470	522
Total interest expense	$ 534	$ 491	$ 551