Shareholders' Equity (Narrative) (Details) $ / shares in Units, $ in Millions	1 Months Ended			12 Months Ended
	Jan. 31, 2022 $ / shares	May 31, 2020 USD ($) shares	Jun. 30, 2015 USD ($)	Dec. 31, 2022 $ / shares	Dec. 31, 2021 $ / shares shares	Dec. 31, 2020 $ / shares shares	Dec. 31, 2019 $ / shares
Shareholders' Equity [Line Items]
Preferred stock, shares outstanding (in shares)					5,011,500	5,011,500
Preferred stock, shares issued (in shares)					5,011,500	5,011,500
Cash dividends declared per common share (usd per share) | $ / shares					$ 1.24	$ 1.12	$ 1.00
Forecast
Shareholders' Equity [Line Items]
Cash dividends declared per common share (usd per share) | $ / shares				$ 1.36
Subsequent event
Shareholders' Equity [Line Items]
Cash dividends declared per common share (usd per share) | $ / shares	$ 0.34
Series D Preferred Stock
Shareholders' Equity [Line Items]
Preferred stock, shares outstanding (in shares)					5,000,000	5,000,000
Preferred stock, shares issued (in shares)					5,000,000	5,000,000
Preferred stock, liquidation value per share (usd per share) | $ / shares					$ 25	$ 25
Sale of stock, proceeds | $			$ 125.0
Preferred stock, dividend rate, percentage			6.50%
Series E Preferred Stock
Shareholders' Equity [Line Items]
Preferred stock, shares outstanding (in shares)					11,500	11,500
Preferred stock, shares issued (in shares)					11,500	11,500
Preferred stock, liquidation value per share (usd per share) | $ / shares					$ 25,000	$ 25,000
Sale of stock, proceeds | $		$ 287.5
Preferred stock, dividend rate, percentage		6.875%
Series E Depositary Shares
Shareholders' Equity [Line Items]
Sale of stock (in shares)		11,500,000
Ratio of preferred stock to depositary shares		0.001
London Interbank Offered Rate (LIBOR) | Series D Preferred Stock
Shareholders' Equity [Line Items]
Preferred stock, dividend rate, percentage, variable spread			4.06%
US Treasury (UST) Interest Rate | Series E Preferred Stock
Shareholders' Equity [Line Items]
Dividend rate, spread on floating rate		0.06507