Investment Securities (Fair Value of Securities Pledged and Accepted as Collateral) (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Summary of Investment Holdings [Line Items]
Permitted by contract or custom to sell or repledge	$ 1,231	$ 755
Permitted amount repledged to others	1,231	755
Asset Pledged as Collateral
Summary of Investment Holdings [Line Items]
Pledged to others	$ 69,330	$ 29,878