Derivative Instruments - Impact of Derivative Instruments on Income Statement (Detail) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Fair Value Hedging \| Interest rate contracts \| Net interest revenue
Derivative Instruments, Gain (Loss) [Line Items]
Gain or (loss) recognized in income on derivatives	$ (148)	$ (95)	$ (151)
Gain or (loss) recognized in hedged item	134	95	149
Cash flow hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gain or (loss) recognized in accumulated OCI on derivatives(effective portion)	(81)	0	2
Gain or (loss) reclassified from accumulated OCI into income (effective portion)	(86)	0	3
Gain or (loss) recognized in income on derivatives (ineffectiveness portion and amount excluded from effectiveness testing)	0	0	0
Cash flow hedges \| Foreign exchange contracts \| Net interest revenue
Derivative Instruments, Gain (Loss) [Line Items]
Gain or (loss) reclassified from accumulated OCI into income (effective portion)	5	0	(1)
Gain or (loss) recognized in income on derivatives (ineffectiveness portion and amount excluded from effectiveness testing)	0	0	0
Cash flow hedges \| Foreign exchange contracts \| Other revenue
Derivative Instruments, Gain (Loss) [Line Items]
Gain or (loss) reclassified from accumulated OCI into income (effective portion)	0	0	0
Gain or (loss) recognized in income on derivatives (ineffectiveness portion and amount excluded from effectiveness testing)	0	0	0
Cash flow hedges \| Foreign exchange contracts \| Trading revenue
Derivative Instruments, Gain (Loss) [Line Items]
Gain or (loss) reclassified from accumulated OCI into income (effective portion)	(89)	0	12
Gain or (loss) recognized in income on derivatives (ineffectiveness portion and amount excluded from effectiveness testing)	0	0	0
Cash flow hedges \| Foreign exchange contracts \| Salary expense
Derivative Instruments, Gain (Loss) [Line Items]
Gain or (loss) reclassified from accumulated OCI into income (effective portion)	(2)	0	(8)
Gain or (loss) recognized in income on derivatives (ineffectiveness portion and amount excluded from effectiveness testing)	0	0	0
Net Investment Hedging \| Foreign exchange contracts \| Net interest revenue
Derivative Instruments, Gain (Loss) [Line Items]
Gain or (loss) reclassified from accumulated OCI into income (effective portion)	0	0	0
Net Investment Hedging \| Foreign exchange contracts \| Other revenue
Derivative Instruments, Gain (Loss) [Line Items]
Gain or (loss) recognized in income on derivatives (ineffectiveness portion and amount excluded from effectiveness testing)	0	0	0
Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest \| Cash flow hedges \| Foreign exchange contracts \| Net interest revenue
Derivative Instruments, Gain (Loss) [Line Items]
Gain or (loss) recognized in accumulated OCI on derivatives(effective portion)	6	0	(1)
Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest \| Cash flow hedges \| Foreign exchange contracts \| Other revenue
Derivative Instruments, Gain (Loss) [Line Items]
Gain or (loss) recognized in accumulated OCI on derivatives(effective portion)	0	0	0
Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest \| Cash flow hedges \| Foreign exchange contracts \| Trading revenue
Derivative Instruments, Gain (Loss) [Line Items]
Gain or (loss) recognized in accumulated OCI on derivatives(effective portion)	(89)	0	12
Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest \| Cash flow hedges \| Foreign exchange contracts \| Salary expense
Derivative Instruments, Gain (Loss) [Line Items]
Gain or (loss) recognized in accumulated OCI on derivatives(effective portion)	2	0	(9)
Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest \| Net Investment Hedging \| Foreign exchange contracts \| Net interest revenue
Derivative Instruments, Gain (Loss) [Line Items]
Gain or (loss) recognized in accumulated OCI on derivatives(effective portion)	$ (58)	$ 148	$ 368

Hedged Items, Gain (Loss) Recognized in Income, Net

No definition available.

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

- Definition

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5618551-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (a),(c),(d),(e)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624171-113959

+ Details

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

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeInstrumentsGainLossLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624171-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4D
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624177-113959

+ Details

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

- Definition

The portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments representing (a) the amount of the hedge ineffectiveness and (b) the amount, if any, excluded from the assessment of hedge effectiveness.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624171-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 25
-Section 50
-Paragraph 1
-Subparagraph (a)(1),(2)
-URI http://asc.fasb.org/extlink&oid=6886632&loc=d3e76258-113986

+ Details

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

- Definition

The effective portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period.

+ References

+ Details

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

- Details

Name:	us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_FairValueHedgingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementLocationAxis=bk_InterestIncomeExpenseNetMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_CashFlowHedgingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_ForeignExchangeContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_OtherIncomeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_TradingRevenueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementLocationAxis=bk_SalaryExpenseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_NetInvestmentHedgingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_OtherComprehensiveIncomeLocationAxis=us-gaap_AccumulatedNetGainLossFromCashFlowHedgesIncludingPortionAttributableToNoncontrollingInterestMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: