Off-Balance Sheet Arrangements, Guarantees and Other Commitments - Summary of Commercial and Standby Letters of Credit (Additional Information) (Details) - Standby Letter of Credit - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Commitments and Contingencies Disclosure [Line Items]
Deferred fees	$ 18	$ 17
Collateral in the form of cash	$ 1,900