Employee Benefit Plans Net Periodic Benefit Cost (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Pension Plan | UNITED STATES
Defined Benefit Plans and Other Postretirement Benefit Plans
Service Cost	$ 2.3	$ 1.9
Interest Cost	22.0	16.8
Expected Return on Plan Assets	(23.0)	(26.5)
Amortization of Net Actuarial (Gain) Loss	3.8	4.1
Amortization of Prior Service Credit	0.0	0.0
Net Periodic Benefit Cost (Credit)	5.1	(3.7)
Pension Plan | UNITED KINGDOM
Defined Benefit Plans and Other Postretirement Benefit Plans
Service Cost	0.0	0.0
Interest Cost	1.9	1.4
Expected Return on Plan Assets	(2.1)	(3.0)
Amortization of Net Actuarial (Gain) Loss	0.6	0.1
Amortization of Prior Service Credit	0.0	0.0
Net Periodic Benefit Cost (Credit)	0.4	(1.5)
Other Postretirement Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans
Service Cost	0.0	0.0
Interest Cost	1.1	0.7
Expected Return on Plan Assets	(0.1)	(0.1)
Amortization of Net Actuarial (Gain) Loss	(2.6)	(0.2)
Amortization of Prior Service Credit	(0.1)	(0.1)
Net Periodic Benefit Cost (Credit)	$ (1.7)	$ 0.3