Mortgage Servicing Assets - Schedule of Changes in Carrying Amount of Mortgage Servicing Assets (Details) - USD ($) $ in Millions |
3 Months Ended | |
|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
|
| Commercial Mortgage Backed Securities | ||
| Servicing Asset at Amortized Cost, Balance [Roll Forward] | ||
| Balance at beginning of period | $ 577 | $ 609 |
| Servicing retained from loan sales | 22 | 15 |
| Purchases | 4 | 4 |
| Amortization | (31) | (31) |
| Balance at end of period | 572 | 597 |
| Fair value at end of period | 733 | 805 |
| Agency residential mortgage-backed securities | ||
| Servicing Asset at Amortized Cost, Balance [Roll Forward] | ||
| Balance at beginning of period | 112 | 111 |
| Servicing retained from loan sales | 5 | 3 |
| Amortization | (3) | (3) |
| Balance at end of period | 114 | 111 |
| Fair value at end of period | $ 140 | $ 138 |