Shareholders' Equity And Earnings Per Share (Narrative) (Detail) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended			3 Months Ended				9 Months Ended		12 Months Ended
	Jun. 30, 2022	May 31, 2020	Jun. 30, 2015	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2022	Dec. 31, 2021
Temporary Equity [Line Items]
Cash dividends declared per common share (usd per share)				$ 0.34	$ 0.34	$ 0.34	$ 0.31	$ 1.02	$ 0.93
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
Sale of stock, proceeds			$ 125.0
Preferred stock, liquidation value per share (usd per share)			$ 25	25			25	25	25		$ 25
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
Sale of stock, proceeds		$ 287.5
Preferred stock, liquidation value per share (usd per share)		$ 25,000		$ 25,000			$ 25,000	$ 25,000	$ 25,000		$ 25,000
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
Public Offering | Common stock
Temporary Equity [Line Items]
Sale of stock (in shares)	3,450,000
Sale of stock, proceeds	$ 285.7