Allowance for Credit Losses and Reserve for Unfunded Lending Commitments - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit loss	$ 15,380	$ 15,296
Allowance for credit losses
Accounts, Notes, Loans and Financing Receivable [Line Items]
Increase (decrease) in allowance for credit loss	84
Allowance for credit loss	$ 15,380	$ 15,296	$ 14,318	$ 13,240