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Investment Securities - Narrative (Details) | 3 Months Ended | 6 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | ---
Jun. 30, 2023 USD ($) Investments | Jun. 30, 2022 USD ($) | Jun. 30, 2023 USD ($) Investments | Jun. 30, 2022 USD ($) | Mar. 31, 2023 USD ($) | Dec. 31, 2022 USD ($) Investments | Mar. 31, 2022 USD ($) | Dec. 31, 2021 USD ($)
Schedule of Held-to-maturity Securities [Line Items] |  |  |  |  |  |  |  |
Allowance for Credit Losses |  |  |  |  |  | $ 0 |  |
Debt Securities, Held-to-maturity, Allowance for Credit Loss | $ 700,000 | $ 1,600,000 | $ 700,000 | $ 1,600,000 | $ 700,000 | 1,900,000 | $ 1,600,000 | $ 0
Interest Receivable | 119,100,000 |  | 119,100,000 |  |  | 118,300,000 |  |
Debt Securities, Available-for-sale, Realized Gain | 0 | 0 |  | 0 |  |  |  |
Debt Securities, Available-for-sale, Realized Loss | 0 | $ 0 | (23,500,000) | $ 0 |  |  |  |
Securities Sold under Agreements to Repurchase, Fair Value of Collateral | 7,227,800,000 |  | 7,227,800,000 |  |  | 4,998,900,000 |  |
Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure | $ 6,455,100,000 |  | $ 6,455,100,000 |  |  | $ 4,432,000,000 |  |
Investment securities in an unrealized loss position (securities) | Investments | 1,030 |  | 1,030 |  |  | 1,222 |  |
Debt Securities, Current | $ 853,000,000 |  | $ 853,000,000 |  |  |  |  |
Callable Within One Year |  |  |  |  |  |  |  |
Schedule of Held-to-maturity Securities [Line Items] |  |  |  |  |  |  |  |
Amortized cost of investment securities callable after one year but within five years | 1,593,800,000 |  | 1,593,800,000 |  |  |  |  |
Fair value of investment securities callable after one year but within five years | 1,521,200,000 |  | 1,521,200,000 |  |  |  |  |
Callable structured notes amortized costs | $ 0 |  | $ 0 |  |  |  |  |

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- Definition Amount of allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 50 -Paragraph 9 -Subparagraph (a) -URI https://asc.fasb.org/extlink&oid=124269663&loc=SL82922900-210455 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 50 -Paragraph 9 -Subparagraph (i) -URI https://asc.fasb.org/extlink&oid=124269663&loc=SL82922900-210455 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (aaa) -URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27161-111563 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 45 -Paragraph 1 -URI https://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454 + Details
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