Investment Securities (Fair Value of Securities Pledged and Accepted as Collateral) (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Summary of Investment Holdings [Line Items]
Permitted by contract or custom to sell or repledge	$ 1,160	$ 1,266
Permitted amount repledged to others	1,160	1,266
Asset Pledged as Collateral
Summary of Investment Holdings [Line Items]
Debt securities, pledged to others	$ 27,347	$ 24,708