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Investment Securities - Amortized Cost and Estimated Fair Value of Securities by Contractual Maturity (Details) - USD ($) $ in Millions | Sep. 30, 2025 | Dec. 31, 2024
--- | --- | ---
Debt Securities, Available-for-sale [Line Items] |  |
Due within one year | $ 1 |
Due from one to five years | 1,345 |
Due from five to ten years | 1,486 |
Due after ten years | 12,220 |
Total debt securities available for sale, net of allowance | 15,052 | $ 10,402
Mortgage- Related Securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Due within one year | 1 |
Due from one to five years | 122 |
Due from five to ten years | 240 |
Due after ten years | 11,964 |
Total debt securities available for sale, net of allowance | 12,327 | 8,573
U.S. Government and GSE Obligations |  |
Debt Securities, Available-for-sale [Line Items] |  |
Due within one year | 0 |
Due from one to five years | 1,080 |
Due from five to ten years | 1,220 |
Due after ten years | 0 |
Total debt securities available for sale, net of allowance | 2,300 |
Corporate and Other Bonds |  |
Debt Securities, Available-for-sale [Line Items] |  |
Due within one year | 0 |
Due from one to five years | 143 |
Due from five to ten years | 26 |
Due after ten years | 38 |
Total debt securities available for sale, net of allowance | 207 |
Asset-Backed Securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Due within one year | 0 |
Due from one to five years | 0 |
Due from five to ten years | 0 |
Due after ten years | 218 |
Total debt securities available for sale, net of allowance | $ 218 | $ 236

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- Definition Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in second through fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-3 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 320 -Name Accounting Standards Codification -Section 50 -Paragraph 3A -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477268/942-320-50-3A + Details
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