Derivative Instruments- Revenue from Foreign Exchange and Other Trading (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
Trading Activity, Gains and Losses, Net [Line Items]
Foreign exchange	$ 130	$ 126	$ 149
Other trading revenue	6	20	12
Foreign exchange and other trading revenue	136	146	161
Fixed Income
Trading Activity, Gains and Losses, Net [Line Items]
Other trading revenue	1	20	8
Credit Derivatives/Other
Trading Activity, Gains and Losses, Net [Line Items]
Other trading revenue	$ 5	$ 0	$ 4

The aggregate foreign currency transaction gain or loss (both realized and unrealized) included in determining net income for the reporting period. Excludes foreign currency transactions designated as hedges of net investment in a foreign entity and intercompany foreign currency transactions that are of a long-term nature, when the entities to the transaction are consolidated, combined, or accounted for by the equity method in the reporting enterprise's financial statements. For certain enterprises, primarily banks, that are dealers in foreign exchange, foreign currency transaction gains or losses may be disclosed as dealer gains or losses. Includes realized and unrealized gains and losses related to the derivatives trading portfolio, including credit default swaps, interest rate swaps and interest rate options.

No definition available.

Name:	bk_ForeignExchangeAndOtherTradingActivities
Namespace Prefix:	bk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration