Commitments and Contingencies - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Commitments to Extend Credit
Letters of credit	$ 3,000	$ 2,900
Allowance for unfunded credit commitments	49	39
Standby Letters of Credit
Commitments to Extend Credit
Letters of credit	2,900	2,900
Commercial Letters of Credit
Commitments to Extend Credit
Letters of credit	$ 31	$ 29