Commitments and Contingent Liabilities- Summary of Off-Balance Sheet Credit Risks, Net of Participations (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Lending commitments
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off Balance Sheet Credit Risk	$ 32,961	[1]	$ 34,039	[1]
Standby letters of credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off Balance Sheet Credit Risk	5,862	[2]	6,721	[2]
Commercial letters of credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off Balance Sheet Credit Risk	339		310
Securities lending indemnifications
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Off Balance Sheet Credit Risk	$ 299,304	[3]	$ 244,382	[3]

[1] no participations at Sept. 30, 2014. Net of participations totaling $6 million at Dec. 31, 2013.

[2] Net of participations totaling $773 million at Sept. 30, 2014 and $720 million at Dec. 31, 2013.

[3] Excludes the indemnification for securities for which BNY Mellon acts as an agent on behalf of CIBC Mellon clients, which totaled $65 billion at Sept. 30, 2014 and $60 billion at Dec. 31, 2013.