Shareholders' Equity (Narrative) (Details) - USD ($) $ / shares in Units, shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Business Acquisition Equity Interests Issued Or Issuable [Line Items]
Number of shares authorized to be repurchased	4.2		4.2
Purchase of treasury stock	$ 118,800,000	$ 0	$ 300,200,000	$ 30,700,000
Treasury stock acquired, Shares,	1.9		4.8	0.5
Treasury Stock Acquired, Average Cost Per Share	$ 63		$ 62.14	$ 60.68
Preferred stock, par value	$ 1	$ 1	$ 1	$ 1	$ 1
Business Bancshares, Inc. [Member]
Business Acquisition Equity Interests Issued Or Issuable [Line Items]
Common stock reissued			2.6