Investments - Schedule of Remaining Contractual Maturities of Repurchase Agreements (Details) - USD ($) $ in Millions |
Sep. 30, 2025 |
Dec. 31, 2024 |
|---|---|---|
| Assets Sold under Agreements to Repurchase [Line Items] | ||
| Payables for repurchase agreements | $ 2,822 | $ 5,716 |
| Less than 30 days | ||
| Assets Sold under Agreements to Repurchase [Line Items] | ||
| Payables for repurchase agreements | 75 | 2,752 |
| 30 – 90 days | ||
| Assets Sold under Agreements to Repurchase [Line Items] | ||
| Payables for repurchase agreements | 0 | 300 |
| 91 days to 1 year | ||
| Assets Sold under Agreements to Repurchase [Line Items] | ||
| Payables for repurchase agreements | 0 | 1,095 |
| Greater than 1 year | ||
| Assets Sold under Agreements to Repurchase [Line Items] | ||
| Payables for repurchase agreements | $ 2,747 | $ 1,569 |