Short-Term Borrowings - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2021
Debt Disclosure [Abstract]
Short-term advances, overnight maturities	$ 0	$ 0
Short-term advances, swapped to a fixed rate	$ 1,300,000,000	$ 1,000,000,000
Short-term advances, swapped to a fixed rate, percentage bearing fixed interest rate	100.00%	100.00%
FHLB
Debt Instrument [Line Items]
Reduction of higher rate outstanding	$ 225,000,000
Hedge termination costs	$ 8,900,000