Investments - Schedule of Remaining Contractual Maturities of Repurchase Agreements (Details) - USD ($) $ in Millions |
Mar. 31, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Assets Sold under Agreements to Repurchase [Line Items] | ||
| Payables for repurchase agreements | $ 3,244 | $ 6,043 |
| Less than 30 days | ||
| Assets Sold under Agreements to Repurchase [Line Items] | ||
| Payables for repurchase agreements | 0 | 2,796 |
| 91 days to 1 year | ||
| Assets Sold under Agreements to Repurchase [Line Items] | ||
| Payables for repurchase agreements | 750 | 0 |
| Greater than 1 year | ||
| Assets Sold under Agreements to Repurchase [Line Items] | ||
| Payables for repurchase agreements | $ 2,494 | $ 3,247 |