Investment Securities - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2023 USD ($) Investment Security	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Summary of Investment Holdings [Line Items]
Gross realized gains(loss) on sale of investment securities	$ 0	$ 0	$ 0
Number of debt securities with aggregate gross unrealized losses | Security	4,022
Unrealized losses on individual debt securities	$ (1,300,000,000)
Cost method investment securities	859,000,000
Investment securities pledged to secure debt carrying value	8,200,000,000	7,900,000,000
Carrying value of investment securities pledged related to repurchase transactions	393,000,000	567,000,000
Available-for-Sale Securities [Member]
Summary of Investment Holdings [Line Items]
Allowance for credit losses	$ 0	$ 0
Government Issued or Guaranteed [Member]
Summary of Investment Holdings [Line Items]
Number of investment securities that exceeded ten percent of shareholders' equity | Investment	0