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Mortgage Servicing Assets - Changes in Carrying Amount of Mortgage Servicing Assets (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2025 | Dec. 31, 2024
Agency commercial mortgage-backed securities |  |
Servicing Asset at Amortized Cost, Balance [Roll Forward] |  |
Balance at beginning of period | $ 609 | $ 638
Servicing retained from loan sales | 83 | 67
Purchases | 11 | 28
Amortization | (125) | (124)
Balance at end of period | 578 | 609
Fair value at end of period | 736 | 819
Agency residential mortgage-backed securities |  |
Servicing Asset at Amortized Cost, Balance [Roll Forward] |  |
Balance at beginning of period | 111 | 108
Servicing retained from loan sales | 14 | 13
Amortization | (12) | (11)
Temporary recoveries (impairments) | 0 | 1
Balance at end of period | 113 | 111
Fair value at end of period | $ 137 | $ 138

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- Definition Servicing Asset At Amortized Cost, Temporary Impairments + References No definition available. + Details
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- Definition Amortized amount of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 860 -SubTopic 50 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481229/860-50-50-4 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 860 -SubTopic 50 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481260/860-50-45-1 Reference 3: http://www.xbrl.org/2003/role/recommendedDisclosureRef -Topic 860 -SubTopic 50 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481260/860-50-45-2 + Details
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- Definition Amount of additions from purchases, assumption or transfer to contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 860 -SubTopic 50 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (a)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481229/860-50-50-4 + Details
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- Definition Amount of amortization of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 860 -SubTopic 50 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (a)(4) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481229/860-50-50-4 + Details
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- Definition Fair value of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 860 -SubTopic 50 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481229/860-50-50-4 + Details
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- Definition Amount of other increase (decrease) to contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 860 -SubTopic 50 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (a)(7) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481229/860-50-50-4 + Details
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