Share Plans - Stock Option Activity (Detail) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2024 USD ($) $ / shares shares
Shares
Beginning balance (shares) | shares	2.3
Granted (shares) | shares	0.2
Exercised (shares) | shares	(0.8)
Ending balance (shares) | shares	1.7
Options exercisable | shares	1.2
Options expected to vest at end of period | shares	0.5
Weighted Average Exercise Price
Beginning balance (USD per share) | $ / shares	$ 45.07
Granted (USD per share) | $ / shares	72.78
Exercised (USD per share) | $ / shares	40.20
Ending Balance (USD per share) | $ / shares	50.35
Options exercisable at end of period (USD per share) | $ / shares	46.36
Options expected to vest at end of period (USD per share) | $ / shares	$ 60.38
Weighted Average Remaining Contractual Life
Ending balance	5 years 7 months 6 days
Options exercisable at end of period	4 years 6 months
Options expected to vest at end of period	8 years 3 months 18 days
Aggregate Intrinsic value
Balance at end of period | $	$ 86.8
Options exercisable at end of period | $	67.2
Options expected to vest at end of period | $	$ 19.2