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Securities - Narrative (Details) | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2024 USD ($) security | Sep. 30, 2023 USD ($) | Sep. 30, 2024 USD ($) security | Sep. 30, 2023 USD ($) | Dec. 31, 2023 USD ($) security
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items] |  |  |  |  |
Number of available-for-sale debt securities in an unrealized loss position | security | 481 |  | 481 |  | 547
Debt Securities, AFS, allowance for credit loss | $ | $ 0 |  | $ 0 |  | $ 0
Provision (reversal of provision) for credit losses | $ | 0 | $ 0 | 0 | $ 0 |
HTM securities allowance for credit loss | $ | 0 |  | 0 |  | 0
Asset Pledged as Collateral |  |  |  |  |
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items] |  |  |  |  |
AFS and HTM debt securities carrying value | $ | $ 5,800,000,000 |  | $ 5,800,000,000 |  | $ 7,000,000,000.0
U.S. government agency and U.S. government-sponsored enterprise mortgage-backed securities |  |  |  |  |
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items] |  |  |  |  |
Number of available-for-sale debt securities in an unrealized loss position | security | 240 |  | 240 |  | 255
Non-agency mortgage-backed securities |  |  |  |  |
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items] |  |  |  |  |
Number of available-for-sale debt securities in an unrealized loss position | security | 88 |  | 88 |  | 99
Corporate debt securities |  |  |  |  |
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items] |  |  |  |  |
Number of available-for-sale debt securities in an unrealized loss position | security | 54 |  | 54 |  | 66

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