Employee Benefit Plans Net Periodic Benefit Cost (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Pension Plan | UNITED STATES
Defined Benefit Plans and Other Postretirement Benefit Plans
Service Cost	$ 10.9	$ 9.1	$ 7.9
Interest Cost	83.3	79.8	84.5
Expected Return on Plan Assets	(99.4)	(104.5)	(103.1)
Amortization of Net Actuarial Loss	20.2	21.7	19.6
Amortization of Prior Service Cost (Credit)	0.0	0.0	(0.3)
Net Periodic Benefit Cost	15.0	6.1	8.6
Pension Plan | UNITED KINGDOM
Defined Benefit Plans and Other Postretirement Benefit Plans
Service Cost	0.0	0.0	0.0
Interest Cost	6.1	5.9	6.2
Expected Return on Plan Assets	(8.9)	(8.9)	(8.8)
Amortization of Net Actuarial Loss	0.9	0.6	0.7
Amortization of Prior Service Cost (Credit)	0.0	0.0	0.0
Net Periodic Benefit Cost	(1.9)	(2.4)	(1.9)
Other Postretirement Benefit Plans
Defined Benefit Plans and Other Postretirement Benefit Plans
Service Cost	0.0	0.0	0.0
Interest Cost	5.3	4.9	5.9
Expected Return on Plan Assets	(0.6)	(0.6)	(0.6)
Amortization of Net Actuarial Loss	(2.5)	0.0	0.0
Amortization of Prior Service Cost (Credit)	(0.2)	(0.2)	(0.4)
Net Periodic Benefit Cost	$ 2.0	$ 4.1	$ 4.9