| Fair Value Measurements - Schedule of Gains (Losses) on Financial Instruments (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
| Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024 | |
| Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ||||
| Total | $ 3 | $ 22 | $ 7 | $ 122 | 
| Loss on specific credit risk | $ 1 | 16 | ||
| 2.75% Exchangeable Senior Debentures | Senior Notes | ||||
| Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ||||
| Stated interest rate (as a percent) | 2.75% | 2.75% | ||
| Debt measured at fair value | ||||
| Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ||||
| Total | $ 3 | 22 | $ 7 | 117 | 
| Loss on specific credit risk | 7 | 30 | ||
| Cumulative loss on credit risk | 17 | 17 | ||
| Other | ||||
| Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ||||
| Total | $ 0 | $ 0 | $ 0 | $ 5 | 
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- Definition Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, Unrealized Gain (Loss) Cumulative Value, before Tax No definition available. 
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- Definition Contractual interest rate for funds borrowed, under the debt agreement. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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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/exampleRef 
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- Definition Amount of realized and unrealized gain (loss) on investment. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Amount, before tax and reclassification adjustment, of unrealized gain (loss) from increase (decrease) in instrument-specific credit risk of financial liability measured under fair value option. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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