Commitments and Contingencies - Pledged Assets (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Total loans and leases	$ 315,699	$ 325,991
Asset Pledged as Collateral
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Securities, fair value	39,702	38,012
Federal Reserve Bank Advances [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Line of Credit Facility, Remaining Borrowing Capacity	54,633	49,250
Federal Reserve Bank Advances [Member] \| Asset Pledged as Collateral
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Total loans and leases	74,463	71,234
FHLB Advances
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Line of Credit Facility, Remaining Borrowing Capacity	23,615	20,770
FHLB Advances \| Asset Pledged as Collateral
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Total loans and leases	$ 68,488	$ 68,988

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Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

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-Name Accounting Standards Codification
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-SubTopic 10
-Section S99
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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://fasb.org/us-gaap/role/ref/legacyRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
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Amount of investment in marketable security.

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