Mortgage Servicing Assets - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2026	Mar. 31, 2025
Commercial Mortgage Backed Securities
Servicing Assets at Fair Value [Line Items]
Contractual fee income from servicing commercial mortgage loans	$ 93	$ 107
Residential mortgage-backed securities
Servicing Assets at Fair Value [Line Items]
Contractual fee income from servicing commercial mortgage loans	$ 13	$ 9

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
-Topic 860
-SubTopic 50
-Name Accounting Standards Codification
-Section 50
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481229/860-50-50-3

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 860
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-Section 50
-Paragraph 3
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-URI https://asc.fasb.org/1943274/2147481229/860-50-50-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 860
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-URI https://asc.fasb.org/1943274/2147481229/860-50-50-3

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 860
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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