Shareholders' Equity Additional Information (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Class of Stock [Line Items]
Repurchase and retirement of common stock	$ 206.2	$ 0.8	$ 378.5	$ 411.3
Number of shares authorized to be repurchased (in shares)	475.6		475.6
Cash dividend paid during period, per share (in dollars per share)	$ 0.64	$ 0.63	$ 1.92	$ 1.89
Common stock excluded from calculation of diluted earnings per share (shares)	1.4	0.8	1.6	0.8
Common Stock
Class of Stock [Line Items]
Repurchase and retirement of common stock (shares)	1.7	0.0	3.2	3.3