Restructuring Charges- Activity in Restructuring Reserve (Detail) (Operational Efficiency Initiatives 2011, USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended	18 Months Ended
Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2011	Jun. 30, 2013
Restructuring Reserve [Roll Forward]
Beginning Balance	$ 70			$ 107
Net additional charges (net recovery/gain)	15	2	107	5
Utilization	(14)			(42)
Ending balance	71	70	107	70
Severance
Restructuring Reserve [Roll Forward]
Beginning Balance	70			78
Net additional charges (net recovery/gain)	15			62
Utilization	(14)			(70)
Ending balance	71	70		70
Other
Restructuring Reserve [Roll Forward]
Beginning Balance	0			29
Net additional charges (net recovery/gain)	0			(57)
Utilization	0			28
Ending balance	$ 0	$ 0		$ 0

Amount charged against earnings in the period for incurred and estimated costs, excluding asset retirement obligations, associated with exit from or disposal of business activities or restructurings pursuant to a program that is planned and controlled by management, and materially changes either the scope of a business undertaken by an entity, or the manner in which that business is conducted. Also includes credit adjustments of prior amounts charged against earnings.

No definition available.

+ Details

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Namespace Prefix:	bk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 420

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SAB TOPIC 5.P.4(b))

-URI http://asc.fasb.org/extlink&oid=27011515&loc=d3e140904-122747

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 5

-Section P

-Subsection 3, 4

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration