Postretirement Benefit Plans - Other Changes in Plan Assets and Net Periodic Postretirement Cost Recognized in Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Net periodic postretirement cost
Service cost	$ 5.9	$ 6.3
Interest cost	19.5	22.9
Amortization of prior service cost		0.0	$ 0.0
Other changes in plan assets and benefit obligations recognized in other comprehensive loss
Prior service cost			0.0
U.S. Pension Plans [Member]
Net periodic postretirement cost
Service cost	3.5	3.2	4.9
Interest cost	13.0	13.1	12.1
Expected return on plan assets	(20.8)	(20.0)	(19.5)
Amortization of net actuarial loss (gain)	7.5	5.8	8.3
Amortization of prior service cost	1.0	0.6	0.8
Net periodic postretirement cost	4.2	2.7	6.6
Effect of curtailment / Special termination benefit	0.0	0.0	1.2
Total net periodic postretirement cost	4.2	2.7	7.8
Other changes in plan assets and benefit obligations recognized in other comprehensive loss
Net actuarial loss (gain)	13.9	37.0	(40.0)
Prior service cost	0.0	4.5	0.0
Amortization of net actuarial (loss) gain	(7.5)	(5.8)	(8.3)
Amortization of prior service cost	(1.0)	(0.6)	(0.8)
Foreign currency translation	0.0	0.0	0.0
Total change recognized in other comprehensive loss	5.4	35.1	(49.1)
Total impact from net periodic postretirement cost and changes in other comprehensive loss	9.6	37.8	(41.3)
International Pension Plan [Member]
Net periodic postretirement cost
Service cost	1.5	1.6	1.7
Interest cost	1.5	2.4	2.5
Expected return on plan assets	0.0	(0.1)	(0.1)
Amortization of net actuarial loss (gain)	1.0	0.4	0.6
Amortization of prior service cost	0.0
Net periodic postretirement cost	4.0	4.3	4.7
Effect of curtailment / Special termination benefit	0.1	0.4	0.0
Total net periodic postretirement cost	4.1	4.7	4.7
Other changes in plan assets and benefit obligations recognized in other comprehensive loss
Net actuarial loss (gain)	(2.9)	13.7	(1.8)
Prior service cost	0.0	0.0	0.0
Amortization of net actuarial (loss) gain	(1.1)	(0.9)	(0.6)
Amortization of prior service cost	0.0	0.0	0.0
Foreign currency translation	(2.5)	(1.8)	0.5
Total change recognized in other comprehensive loss	(6.5)	11.0	(1.9)
Total impact from net periodic postretirement cost and changes in other comprehensive loss	(2.4)	15.7	2.8
Pension [Member]
Net periodic postretirement cost
Service cost	5.0	4.8	6.6
Interest cost	14.5	15.5	14.6
Expected return on plan assets	(20.8)	(20.1)	(19.6)
Amortization of net actuarial loss (gain)	8.5	6.2	8.9
Amortization of prior service cost	1.0	0.6	0.8
Net periodic postretirement cost	8.2	7.0	11.3
Effect of curtailment / Special termination benefit	0.1	0.4	1.2
Total net periodic postretirement cost	8.3	7.4	12.5
Other changes in plan assets and benefit obligations recognized in other comprehensive loss
Net actuarial loss (gain)	11.0	50.7	(41.8)
Prior service cost	0.0	4.5
Amortization of net actuarial (loss) gain	(8.6)	(6.7)	(8.9)
Amortization of prior service cost	(1.0)	(0.6)	(0.8)
Foreign currency translation	(2.5)	(1.8)	0.5
Total change recognized in other comprehensive loss	(1.1)	46.1	(51.0)
Total impact from net periodic postretirement cost and changes in other comprehensive loss	7.2	53.5	(38.5)
Other Postretirement Benefit Plan [Member]
Net periodic postretirement cost
Service cost	0.9	1.5	2.9
Interest cost	5.0	7.4	8.3
Expected return on plan assets	(0.9)	(0.7)	(0.6)
Amortization of net actuarial loss (gain)	4.6	2.7	4.3
Amortization of prior service cost	(11.0)	(6.6)	(0.4)
Net periodic postretirement cost	(1.4)	4.3	14.5
Effect of curtailment / Special termination benefit	(4.2)	0.0	0.0
Total net periodic postretirement cost	(5.6)	4.3	14.5
Other changes in plan assets and benefit obligations recognized in other comprehensive loss
Net actuarial loss (gain)	7.7	26.3	(31.1)
Prior service cost	0.0	(58.7)	(19.0)
Amortization of net actuarial (loss) gain	(4.6)	(2.7)	(4.3)
Amortization of prior service cost	11.0	6.6	0.4
Acceleration of prior service costs	6.2	0.0	0.0
Total change recognized in other comprehensive loss	20.3	(28.5)	(54.0)
Total impact from net periodic postretirement cost and changes in other comprehensive loss	$ 14.7	$ (24.2)	$ (39.5)