Reclassification out of AOCI (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Cash Flow Hedges, net of tax:
Gains on cash flow hedges - Pre Tax	$ 0.1	$ 6.1	$ 0.2	$ 7.5
Gains on cash flow hedges - Tax		(2.8)		(3.3)
Amount of Gain/(Loss) Reclassified from AOCI into Income, net of Tax	0.1	3.3	0.2	4.2
Pension and Other Post-Retirement Benefits, net of tax:
Amortization of actuarial losses and prior service costs included in net income - Pre Tax	(1.0)	(1.9)	(2.4)	(4.3)
Amortization of actuarial losses and prior service costs included in net income - Tax	0.3	0.8	0.7	1.7
Amortization of actuarial losses and prior service costs included in net income - Net of Tax	(0.7)	(1.1)	(1.7)	(2.6)
(Losses) Income Attributable to Reclassification Out Of AOCI Net Of Tax	(0.6)	2.2	(1.5)	1.6
Operating Expense [Member]
Pension and Other Post-Retirement Benefits, net of tax:
Amortization of actuarial losses and prior service costs included in net income - Pre Tax	(0.7)	(1.2)	(1.6)	(2.7)
SG&A Expense [Member]
Pension and Other Post-Retirement Benefits, net of tax:
Amortization of actuarial losses and prior service costs included in net income - Pre Tax	(0.3)	(0.7)	(0.8)	(1.6)
Currency Swap [Member] | Interest Expense [Member]
Cash Flow Hedges, net of tax:
Gains on cash flow hedges - Pre Tax	$ 0.1		$ 0.2
Currency Swap [Member] | Other Nonoperating Income (Expense) [Member]
Cash Flow Hedges, net of tax:
Gains on cash flow hedges - Pre Tax		7.1		8.6
Treasury Rate Lock [Member] | Interest Expense [Member]
Cash Flow Hedges, net of tax:
Gains on cash flow hedges - Pre Tax		$ (1.0)		$ (1.1)