Shareholders' Equity And Earnings Per Share (Narrative) (Detail) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended		3 Months Ended		12 Months Ended
	May 31, 2020	Jun. 30, 2015	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2022	Dec. 31, 2021
Temporary Equity [Line Items]
Cash dividends declared per common share (usd per share)			$ 0.34	$ 0.31
Forecast
Temporary Equity [Line Items]
Cash dividends declared per common share (usd per share)					$ 1.36
Series D Preferred Stock
Temporary Equity [Line Items]
Sale of stock (in shares)		5,000,000
Preferred stock, liquidation value per share (usd per share)		$ 25	25	25		$ 25
Sale of stock, proceeds		$ 125.0
Preferred stock, dividend rate, percentage		6.50%
Series D Preferred Stock | London Interbank Offered Rate (LIBOR)
Temporary Equity [Line Items]
Preferred stock, dividend rate, percentage, variable spread		4.06%
Series E Preferred Stock
Temporary Equity [Line Items]
Sale of stock (in shares)	11,500
Preferred stock, liquidation value per share (usd per share)	$ 25,000		$ 25,000	$ 25,000		$ 25,000
Sale of stock, proceeds	$ 287.5
Preferred stock, dividend rate, percentage	6.875%
Series E Preferred Stock | US Treasury (UST) Interest Rate
Temporary Equity [Line Items]
Dividend rate, spread on floating rate	0.06507
6.875% Fixed-Rate Reset Non-Cumulative Perpetual Preferred Stock, Series E, no par value
Temporary Equity [Line Items]
Sale of stock (in shares)	11,500,000