Commitments and Contingencies Outstanding Commitments to Extend Credit and Letters of Credit (Details) - USD ($) $ in Thousands |
Mar. 31, 2021 |
Dec. 31, 2020 |
---|---|---|
Commitments to Extend Credit [Member] | ||
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] | ||
Valuation allowances and reserves, balance | $ 9,018,523 | $ 8,651,055 |
Standby Letters of Credit [Member] | ||
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] | ||
Valuation allowances and reserves, balance | 295,516 | 298,750 |
Commercial Letters of Credit [Member] | ||
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items] | ||
Valuation allowances and reserves, balance | $ 57,917 | $ 56,229 |