Debt - Narrative (Details) $ in Millions	12 Months Ended
Dec. 31, 2022 USD ($) subsidiaryBusinessTrust class
Debt Instrument [Line Items]
Number of classes of financial instruments \| class	2
Number of business subsidiary trusts \| subsidiaryBusinessTrust	2
Federal Reserve Bank of New York
Debt Instrument [Line Items]
Collateral, at carrying cost	$ 939
Collateral, at fair value	890
Federal Home Loan Bank of New York
Debt Instrument [Line Items]
Collateral, at carrying cost	899
Collateral, at fair value	800
Interest Rate Swap
Debt Instrument [Line Items]
Amount of hedged item	$ 20
ACST III \| London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate	2.00%
ACST III \| Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Basis spread on variable rate	2.00%
Junior Subordinated Debt, Preferred Securities \| ACST II \| London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate	3.15%
Junior Subordinated Debt, Preferred Securities \| ACST II \| Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Basis spread on variable rate	3.15%

Number Of Business Subsidiary Trusts

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- Definition

Number Of Classes Of Financial Instruments

+ References

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+ Details

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- Definition

Securities Held As Collateral, At Carrying Cost

+ References

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- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

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- 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

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- Definition

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

+ References

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- Definition

The carrying amount (fair value) as of the balance sheet date of securities held that had been pledged by counterparties under financing and lending arrangements, pursuant to which the entity has the right by agreement or custom to sell or re-pledge such securities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 5
-URI https://asc.fasb.org/extlink&oid=123577603&loc=d3e5086-111524

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