Deposits and Borrowings - Schedule of Components of Interest Expense on Short-Term Borrowings and Long-Term Debt (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Short-term borrowings:
Federal funds purchased and securities loaned or sold under agreements to repurchase	$ 1	$ 0
FHLB advances	0	8
Total short-term borrowings	1	8
Long-term debt:
Securitized debt obligations	48	33
Senior and subordinated notes	106	79
Other long-term borrowings	23	7
Total long-term debt	177	119
Total interest expense	$ 178	$ 127