Goodwill, Mortgage Servicing Rights, and Other Intangible Assets - Key Economic Assumptions (Details) - USD ($) $ in Millions |
6 Months Ended | 12 Months Ended |
|---|---|---|
Jun. 30, 2025 |
Dec. 31, 2024 |
|
| Goodwill and Intangible Assets Disclosure [Abstract] | ||
| Weighted-average prepayment speed assumption (constant prepayment rate) | 6.88% | 6.19% |
| Impact on fair value of 10% adverse change | $ (180) | $ (209) |
| Impact on fair value of 20% adverse change | $ (351) | $ (406) |
| Weighted-average option adjusted spread | 6.10% | 5.97% |
| Impact on fair value of a 100 basis point adverse change | $ (383) | $ (391) |
| Impact on fair value of a 200 basis point adverse change | $ (735) | $ (751) |