Available-for-sale Securities (Summary of Available-for-sale Securities in a Continuous Unrealized Loss Position) (Details) - Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] - USD ($) $ in Millions |
Jun. 30, 2026 |
Dec. 31, 2025 |
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| Debt Securities, Available-for-sale [Line Items] | ||
| Available For Sale Securities Continuous Unrealized Loss Position Less Than 12 Months Aggregate Losses Accumulated In Investments | $ 3,664 | $ 673 |
| Available-for sale. Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | (10) | (2) |
| Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer | 147 | 196 |
| Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | 0 | 0 |
| Available-for-Sale, Unrealized Loss Position | 3,811 | 869 |
| Available-for-Sale, Unrealized Loss Position, Accumulated Loss | $ (10) | $ (2) |
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- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset. Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
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- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset. Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
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- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position without allowance for credit loss. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset. Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
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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. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Details
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