Securities-Net Securities Gains (Losses) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Securities [Abstract]
Realized gross gains	$ 25bk_RealizedSecuritiesGrossGains	$ 41bk_RealizedSecuritiesGrossGains	$ 30bk_RealizedSecuritiesGrossGains
Realized gross losses	0bk_RealizedSecuritiesGrossLosses	0bk_RealizedSecuritiesGrossLosses	(3)bk_RealizedSecuritiesGrossLosses
Recognized gross impairments	(1)	(10)	(5)
Net securities gains	$ 24bk_NetSecuritiesGainLoss	$ 31bk_NetSecuritiesGainLoss	$ 22bk_NetSecuritiesGainLoss

This item represents the total realized gain (loss) included in earnings for the period as a result of selling marketable securities categorized as available-for-sale or held-to-maturity. Additionally, this item would include any losses recognized for other than temporary impairments of the subject investments in debt and equity securities.

No definition available.

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