Commitments and Contingent Liabilities- Summary of Off-Balance Sheet Credit Risks, Net of Participations (Parenthetical) (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Securities Lending Indemnifications Joint Venture	$ 65,000,000,000	$ 60,000,000,000
Lending commitments
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet credit risks participations	6,000,000	6,000,000
Standby letters of credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off-balance sheet credit risks participations	$ 688,000,000	$ 720,000,000