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Debt Securities (Amortized Cost, Unrealized Gains And Losses, And Fair Value Of Investment Securities) (Details) - USD ($) $ in Millions | Sep. 30, 2025 | Dec. 31, 2024
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Debt and Equity Securities, FV-NI [Line Items] |  |
Available-for-sale securities, amortized cost | $ 11,334 | $ 8,858
Available-for-sale securities, unrealized gains | 89 | 8
Available-for-sale securities, unrealized losses | (410) | (591)
Available for sale, at fair value | 11,013 | 8,275
Investment securities held to maturity | 18 | 2
Held-to-maturity securities, unrealized gains | 0 | 1
Held-to-maturity securities, unrealized losses | 0 | 0
Held-to-maturity securities, fair value | 18 | 3
U.S. Treasury and agencies |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Available-for-sale securities, amortized cost | 1,332 | 1,496
Available-for-sale securities, unrealized gains | 6 | 1
Available-for-sale securities, unrealized losses | (43) | (74)
Available for sale, at fair value | 1,295 | 1,423
Obligations of states and political subdivisions |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Available-for-sale securities, amortized cost | 1,621 | 1,055
Available-for-sale securities, unrealized gains | 34 | 3
Available-for-sale securities, unrealized losses | (18) | (32)
Available for sale, at fair value | 1,637 | 1,026
Mortgage-backed securities and collateralized mortgage obligations |  |
Debt and Equity Securities, FV-NI [Line Items] |  |
Available-for-sale securities, amortized cost | 8,381 | 6,307
Available-for-sale securities, unrealized gains | 49 | 4
Available-for-sale securities, unrealized losses | (349) | (485)
Available for sale, at fair value | 8,081 | 5,826
Investment securities held to maturity | 18 | 2
Held-to-maturity securities, unrealized gains | 0 | 1
Held-to-maturity securities, unrealized losses | 0 | 0
Held-to-maturity securities, fair value | $ 18 | $ 3

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- Definition Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) 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 -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-2 + Details
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- Definition Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) 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 -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-2 + Details
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