Investment Securities - Amortized Cost, Fair Value of MBS Issued by FNMA and FHLMC Exceeding 10% of Shareholders' Equity (Details) $ in Millions	Jun. 30, 2023 USD ($)
FNMA investments
Schedule of Debt Securities Exceeding Ten Percent of Stockholders Equity [Line Items]
Securities, amortized cost	$ 41,052
Securities, fair value	34,325
FHLMC investments
Schedule of Debt Securities Exceeding Ten Percent of Stockholders Equity [Line Items]
Securities, amortized cost	41,601
Securities, fair value	$ 34,612