Derivative Instruments and Hedging Activities Disclosure [Line Items]

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- Definition

Hedged Instrument Maturity Lower Limit

+ References

No definition available.

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- Definition

Hedged Instruments Maturity Upper Limit

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No definition available.

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- Definition

Value At Risk Assumed Holding Period For Instruments

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No definition available.

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- Definition

VAR confidence level

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No definition available.

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- Definition

The aggregate fair value of additional assets that would be required to be posted as collateral for derivative instruments with credit-risk-related contingent features if the credit-risk-related contingent features were triggered at the end of the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 815
-SubTopic 10
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-Section 55
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- Definition

The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 30
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- Definition

Amount of hedged item in hedging relationship. Excludes hedged asset or liability.

+ References

No definition available.

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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-SubTopic 10
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- Definition

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

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- Definition

Nominal or face amount used to calculate payment on derivative.

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Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition

Period remaining until the derivative contract matures, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

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- Definition

Amount of asset hedged in portfolio layer hedging relationship, expected to be remaining at end of hedging relationship.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
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- Definition

Amount, before tax and after reclassification, of gain (loss) from derivative instrument designated and qualifying cash flow hedge included in assessment of hedge effectiveness.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
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-Name Accounting Standards Codification
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Derivative instruments - Narrative (Details) - USD ($)	3 Months Ended			9 Months Ended
Derivative instruments - Narrative (Details) - USD ($)	Sep. 30, 2025	Jun. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Counterparty default losses recorded	$ 0
Value-at-risk methodology assumed holding period for instruments				1 day
Value-at-risk methodology confidence level percentage				99.00%
Gain or (loss) recognized in income on derivatives	(3,000,000)	$ (1,000,000)	$ (1,000,000)	$ (7,000,000)	$ 5,000,000
Additional collateral The Bank of New York Mellon would have to post for existing collateral arrangements, if The Bank of New York Mellon had fallen below investment grade	61,000,000			61,000,000		$ 351,000,000
Fair value hedging \| Loans
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Interest rate swaps designated as portfolio layer method fair value hedges of loans	3,000,000,000			3,000,000,000		3,200,000,000
Fair value hedging \| Securities – Available-for-sale
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Interest rate swaps designated as portfolio layer method fair value hedges of loans	14,300,000,000			14,300,000,000		12,100,000,000
Interest rate swap \| Fair value hedging \| Loans
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Interest rate swaps designated as portfolio layer method fair value hedges of loans	1,400,000,000			1,400,000,000
Foreign exchange contracts \| Forecasted Foreign Currency
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Gain (loss) to be reclassified in next 12 months from AOCI to earnings				(16,000,000)
Foreign exchange contracts \| Cash flow hedges \| Forecasted Foreign Currency
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Hedged financial instruments, notional amount of derivative	760,000,000			$ 760,000,000
Original maturities, maximum, of hedged instruments				15 months
Pre-tax gain (loss) recognized in OCI related to cash flow hedges				$ (16,000,000)
Foreign exchange contracts \| Net investment hedging
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Hedged financial instruments, notional amount of derivative	$ 10,700,000,000			$ 10,700,000,000
Foreign Exchange Forward
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Hedging derivatives, maturities, maximum	1 year			1 year
Securities – Available-for-sale \| Interest rate swap
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Hedged financial instruments	$ 35,200,000,000			$ 35,200,000,000
Hedged financial instruments, notional amount of derivative	35,000,000,000.0			35,000,000,000.0
Long-term debt \| Interest rate swap
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Hedged financial instruments	29,800,000,000			29,800,000,000
Hedged financial instruments, notional amount of derivative	29,800,000,000			$ 29,800,000,000
Original maturities, minimum, of hedged instruments				5 years
Original maturities, maximum, of hedged instruments				30 years
Not Designated as Hedging Instrument, Economic Hedge \| Equity Swap
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Gain or (loss) recognized in income on derivatives	12,000,000	$ 15,000,000	$ 11,000,000	$ 19,000,000	$ 22,000,000
Designated as hedging \| Fair value hedging \| Loans
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Interest rate swaps designated as portfolio layer method fair value hedges of loans	1,400,000,000			1,400,000,000		1,400,000,000
Designated as hedging \| Fair value hedging \| Securities – Available-for-sale
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Interest rate swaps designated as portfolio layer method fair value hedges of loans	6,800,000,000			6,800,000,000		6,200,000,000
Designated as hedging \| Foreign exchange contracts
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Hedged financial instruments, notional amount of derivative	$ 11,506,000,000			$ 11,506,000,000		$ 12,048,000,000