Off-Balance Sheet Arrangements, Guarantees and Other Commitments - Summary of Commercial and Standby Letters of Credit (Details) $ in Thousands	Dec. 31, 2020 USD ($)
Other Commitments [Line Items]
Expires In One Year or Less	$ 2,920,989
Expires After One Year	86,129
Total Amount Outstanding	3,007,118
Maximum Amount of Future Payments	3,007,118
Financial standby letters of credit
Other Commitments [Line Items]
Expires In One Year or Less	2,807,942
Expires After One Year	66,641
Total Amount Outstanding	2,874,583
Maximum Amount of Future Payments	2,874,583
Performance standby letters of credit
Other Commitments [Line Items]
Expires In One Year or Less	108,681
Expires After One Year	19,488
Total Amount Outstanding	128,169
Maximum Amount of Future Payments	128,169
Commercial letters of credit
Other Commitments [Line Items]
Expires In One Year or Less	4,366
Expires After One Year	0
Total Amount Outstanding	4,366
Maximum Amount of Future Payments	$ 4,366