Stock Option Plans - Stock Option Activity and Related Information (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Shares Under Option, Beginning balance	7.5	7.9
Shares Under Option, Granted	1.6	1.6
Shares Under Option, Exercised	(1.4)	(1.8)
Shares Under Option, Forfeited or canceled	(0.2)	(0.2)
Shares Under Option, Ending balance	7.5	7.5
Shares Under Option, Exercisable at end of year	2.1	1.9
Shares Under Option, Ending unvested and expected to vest	5.1	5.3
Weighted Average Exercise Price, Beginning balance	$ 65.09	$ 56.40
Weighted Average Exercise Price, Granted	127.90	86.17
Weighted Average Exercise Price, Exercised	49.10	45.80
Weighted Average Exercise Price, Forfeited or canceled	88.84	65.87
Weighted Average Exercise Price, Ending balance	81.30	65.09
Weighted Average Exercise Price, Exercisable at end of year	51.46	47.17
Weighted Average Exercise Price, Ending unvested and expected to vest	$ 91.56	$ 70.74
Weighted Average Remaining Contractual Term (in years), Ending balance	3 years 10 months 24 days	3 years 10 months 9 days
Weighted Average Remaining Contractual Term (in years), Exercisable at end of year	1 year 6 months 25 days	1 year 9 months 29 days
Weighted Average Remaining Contractual Term (in years), Ending unvested and expected to vest	4 years 8 months 19 days	4 years 6 months 3 days
Aggregate Intrinsic Value, Ending Balance	$ 666.3	$ 437.9
Aggregate Intrinsic Value, Exercisable at end of year	242.3	147.2
Aggregate Intrinsic Value, Ending unvested and expected to vest	$ 401.7	$ 278.1