Asset Quality - Nonperforming Assets and Past Due Loans (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
Receivables [Abstract]
Total nonperforming loans	$ 449	$ 508	$ 650
Nonperforming loans held for sale	1	1	23
OREO	12	15	21
Other nonperforming assets	7	7	11
Total nonperforming assets	469	531	705
Nonperforming assets from discontinued operations - education lending	20	25	15
Restructured loans included in nonperforming loans	178	214	178
Restructured loans with an allocated specific allowance	51	71	52
Specifically allocated allowance for restructured loans	32	35	30
Accruing loans past due 90 days or more	89	71	83
Accruing loans past due 30 through 89 days	$ 267	$ 318	$ 368