Commitments and Contingent Liabilities- Summary of Off-Balance Sheet Credit Risks, Net of Participations (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013		Dec. 31, 2012
Lending commitments
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off Balance Sheet Credit Risk	$ 33,184	[1]	$ 31,265	[1]
Standby letters of credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off Balance Sheet Credit Risk	6,737	[2]	7,167	[2]
Commercial letters of credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off Balance Sheet Credit Risk	374		219
Securities lending indemnifications
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off Balance Sheet Credit Risk	$ 268,637	[3]	$ 245,717	[3]

[1] Net of participations totaling $326 million at Sept. 30, 2013 and $350 million at Dec. 31, 2012.

[2] Net of participations totaling $793 million at Sept. 30, 2013 and $1.0 billion at Dec. 31, 2012.

[3] Excludes securities lending activity at the CIBC Mellon joint venture of $65 billion at Sept. 30, 2013 and $66 billion at Dec. 31, 2012.