Commitments and Contingent Liabilities- Significant Industry Concentrations Related to Credit Exposure (Detail) (USD $)	Sep. 30, 2014		Dec. 31, 2013
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loans	$ 57,527,000,000	[1]	$ 51,657,000,000	[1]
Financial institutions
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loans	14,574,000,000		14,359,000,000
Unfunded commitments	15,500,000,000
Total exposure	30,100,000,000
Financial institutions | Banks
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loans	9,000,000,000
Unfunded commitments	1,600,000,000
Total exposure	10,600,000,000
Financial institutions | Asset managers
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loans	1,500,000,000
Unfunded commitments	4,600,000,000
Total exposure	6,100,000,000
Financial institutions | Securities industry
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loans	3,600,000,000
Unfunded commitments	1,300,000,000
Total exposure	4,900,000,000
Financial institutions | Insurance
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loans	100,000,000
Unfunded commitments	4,000,000,000
Total exposure	4,100,000,000
Financial institutions | Government
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loans	0
Unfunded commitments	3,000,000,000
Total exposure	3,000,000,000
Financial institutions | Other
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loans	400,000,000
Unfunded commitments	1,000,000,000
Total exposure	1,400,000,000
Commercial
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loans	1,558,000,000		1,647,000,000
Unfunded commitments	18,700,000,000
Total exposure	20,200,000,000
Commercial | Services and other
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loans	700,000,000
Unfunded commitments	5,800,000,000
Total exposure	6,500,000,000
Commercial | Energy and utilities
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loans	400,000,000
Unfunded commitments	5,700,000,000
Total exposure	6,100,000,000
Commercial | Manufacturing
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loans	300,000,000
Unfunded commitments	5,600,000,000
Total exposure	5,900,000,000
Commercial | Media and telecom
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Loans	100,000,000
Unfunded commitments	1,600,000,000
Total exposure	$ 1,700,000,000

[1] Net of unearned income of $894 million at Sept. 30, 2014 and $1,020 million at Dec. 31, 2013 primarily on domestic and foreign lease financings.