Loans and asset quality - Allowance for Credit Losses Activity (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	$ 275	$ 280	$ 344
Charge-offs	(2)	(172)	(20)
Recoveries	19	7	4
Net recoveries	17	(165)	(16)
Provision	(11)	160	(48)
Ending balance	281	275	280
Allowance for:
Loan losses	169	157	191
Lending-related commitments	112	118	89
Individually evaluated for impairment:
Loan balance	9	180	8
Allowance for loan losses	5	2	1
Collectively evaluated for impairment:
Loan balance	64,449	63,101	59,103
Allowance for loan losses	164	155	190
Loans	64,458	63,703
Total Domestic
Collectively evaluated for impairment:
Loans	50,425	49,351
Commercial
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	82	60	83
Charge-offs	0	0	(12)
Recoveries	0	0	1
Net recoveries	0	0	(11)
Provision	0	22	(12)
Ending balance	82	82	60
Allowance for:
Loan losses	25	24	17
Lending-related commitments	57	58	43
Individually evaluated for impairment:
Loan balance	0	0	0
Allowance for loan losses	0	0	0
Collectively evaluated for impairment:
Loan balance	2,286	2,115	1,390
Allowance for loan losses	25	24	17
Loans	2,617	2,342
Commercial \| Total Domestic
Collectively evaluated for impairment:
Loans	2,286	2,115
Commercial real estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	59	50	41
Charge-offs	0	0	(2)
Recoveries	0	0	0
Net recoveries	0	0	(2)
Provision	14	9	11
Ending balance	73	59	50
Allowance for:
Loan losses	52	37	32
Lending-related commitments	21	22	18
Individually evaluated for impairment:
Loan balance	0	1	0
Allowance for loan losses	0	1	0
Collectively evaluated for impairment:
Loan balance	4,639	3,496	2,503
Allowance for loan losses	52	36	32
Loans	4,654	3,945
Commercial real estate \| Total Domestic
Collectively evaluated for impairment:
Loans	4,639	3,899
Financial institutions
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	31	31	49
Charge-offs	0	(170)	0
Recoveries	13	1	1
Net recoveries	13	(169)	1
Provision	(18)	169	(19)
Ending balance	26	31	31
Allowance for:
Loan losses	8	9	17
Lending-related commitments	18	22	14
Individually evaluated for impairment:
Loan balance	0	171	0
Allowance for loan losses	0	0	0
Collectively evaluated for impairment:
Loan balance	6,342	6,469	5,603
Allowance for loan losses	8	9	17
Loans	14,689	15,899
Financial institutions \| Total Domestic
Collectively evaluated for impairment:
Loans	6,342	6,640
Lease financings
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	15	32	37
Charge-offs	0	0	0
Recoveries	0	0	0
Net recoveries	0	0	0
Provision	(2)	(17)	(5)
Ending balance	13	15	32
Allowance for:
Loan losses	13	15	32
Lending-related commitments	0	0	0
Individually evaluated for impairment:
Loan balance	4	0	0
Allowance for loan losses	2	0	0
Collectively evaluated for impairment:
Loan balance	985	1,007	1,282
Allowance for loan losses	11	15	32
Lease financings \| Total Domestic
Collectively evaluated for impairment:
Loans	989	1,007
Wealth management loans and mortgages
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	19	22	24
Charge-offs	0	0	(1)
Recoveries	0	0	0
Net recoveries	0	0	(1)
Provision	4	(3)	(1)
Ending balance	23	19	22
Allowance for:
Loan losses	19	15	17
Lending-related commitments	4	4	5
Individually evaluated for impairment:
Loan balance	5	8	8
Allowance for loan losses	3	1	1
Collectively evaluated for impairment:
Loan balance	15,550	13,239	11,087
Allowance for loan losses	16	14	16
Loans	15,654	13,347
Wealth management loans and mortgages \| Total Domestic
Collectively evaluated for impairment:
Loans	15,555	13,247
Other residential mortgages
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	34	41	54
Charge-offs	(2)	(2)	(2)
Recoveries	5	6	2
Net recoveries	3	4	0
Provision	(9)	(11)	(13)
Ending balance	28	34	41
Allowance for:
Loan losses	28	34	41
Lending-related commitments	0	0	0
Individually evaluated for impairment:
Loan balance	0	0	0
Allowance for loan losses	0	0	0
Collectively evaluated for impairment:
Loan balance	854	1,035	1,222
Allowance for loan losses	28	34	41
Loans	854	1,055
Other residential mortgages \| Total Domestic
Collectively evaluated for impairment:
Loans	854	1,055
All Other
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	0	0	0
Charge-offs	0	0	0
Recoveries	0	0	0
Net recoveries	0	0	0
Provision	0	0	0
Ending balance	0	0	0
Allowance for:
Loan losses	0	0	0
Lending-related commitments	0	0	0
Individually evaluated for impairment:
Loan balance	0	0	0
Allowance for loan losses	0	0	0
Collectively evaluated for impairment:
Loan balance	19,760	21,388	22,495
Allowance for loan losses	0	0	0
Foreign
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	35	44	56
Charge-offs	0	0	(3)
Recoveries	1	0	0
Net recoveries	1	0	(3)
Provision	0	(9)	(9)
Ending balance	36	35	44
Allowance for:
Loan losses	24	23	35
Lending-related commitments	12	12	9
Individually evaluated for impairment:
Loan balance	0	0	0
Allowance for loan losses	0	0	0
Collectively evaluated for impairment:
Loan balance	14,033	14,352	13,521
Allowance for loan losses	24	23	35
Overdrafts
Collectively evaluated for impairment:
Loans	5,461	4,483
Overdrafts \| Total Domestic
Collectively evaluated for impairment:
Loans	1,055	911	1,348
Margin loans
Collectively evaluated for impairment:
Loans	17,590	19,573
Margin loans \| Total Domestic
Collectively evaluated for impairment:
Loans	17,503	19,340	20,034
Other \| Total Domestic
Collectively evaluated for impairment:
Loans	$ 1,202	$ 1,137	$ 1,113

Financing Receivable, Allowance for Credit Losses, Net Charge Offs

No definition available.

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

- Definition

Financing Receivable, Allowance for Credit Losses, Unfunded Commitments

+ References

No definition available.

+ Details

Name:	bk_FinancingReceivableAllowanceForCreditLossesUnfundedCommitments
Namespace Prefix:	bk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Loans and Allowance for Loan Losses Collectively Evalueated for Impairment [Abstract]

+ References

No definition available.

+ Details

Name:	bk_LoansandAllowanceforLoanLossesCollectivelyEvalueatedforImpairmentAbstract
Namespace Prefix:	bk_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

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

- Definition

A valuation allowance for financing receivables that are expected to be uncollectible.

+ References

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLosses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

+ References

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

+ References

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of recovery of financing receivables doubtful of collection that were previously charged off.

+ References

+ Details

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

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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

- Definition

Amount of direct write-downs of financing receivables charged against the allowance.

+ References

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The balance of financing receivables that were collectively evaluated for impairment.

+ References

+ Details

Name:	us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The balance of financing receivables that were individually evaluated for impairment.

+ References

+ Details

Name:	us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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

- Definition

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953423-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953423-111524

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7(d))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB Topic 6.L.1)
-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74567-122707

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (b)(1)(ii)
-URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544

+ Details

Name:	us-gaap_LoansAndLeasesReceivableAllowance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=65884687&loc=d3e4428-111522

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5074-111524

+ Details

Name:	us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of expense related loan transactions, lease transactions, credit loss from transactions other than loan and lease transactions, and other loss based on assessment of uncollectability from the counterparty to reduce the account to their net realizable value.

+ References

+ Details

Name:	us-gaap_ProvisionForLoanLeaseAndOtherLosses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_ProductOrServiceAxis=bk_DomesticMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=bk_FinancialInstitutionsPortfolioMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_FinanceLeasesPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=bk_WealthManagementLoansAndMortgagesPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ResidentialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=bk_AllOtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=bk_ForeignMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_BankOverdraftsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=bk_MarginLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=bk_OtherLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: