Securities Purchased Under Agreements to Resell and Securities Sold Under Agreements to Repurchase - Securities Purchased under Agreements to Resell (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Investments, Debt and Equity Securities [Abstract]
Balance at December 31	$ 1,070.3	$ 686.4
Average Balance During the Year	$ 1,071.2	$ 1,067.4
Average Interest Rate Earned During the Year	9.68%	0.33%
Maximum Month-End Balance During the Year	$ 1,320.8	$ 1,819.1