Leases, Premises and Equipment - Schedule of Supplemental Balance Sheet Information (Details) - USD ($) $ in Millions |
Jun. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Operating Leases: | ||
| Operating lease right-of-use assets | $ 373 | $ 380 |
| Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] | Other assets | Other assets |
| Operating lease liabilities | $ 418 | $ 427 |
| Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration] | Operating lease liabilities | Operating lease liabilities |
| Weighted average remaining lease term | 9 years 9 months 18 days | 10 years 1 month 6 days |
| Weighted average discount rate % | 4.75% | 4.79% |