Components of Net Periodic Benefit Expense (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Other Postretirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0.1	$ 0.2	$ 0.4	$ 0.5
Interest cost	1.7	2.0	5.1	6.0
Expected return on assets	(0.1)	(0.1)	(0.3)	(0.4)
Amortization of prior service (benefit) cost	0.3	0.4	0.9	1.3
Recognized net actuarial loss	0.7	0.8	2.1	2.5
Net periodic benefit expense	2.7	3.3	8.2	9.9
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	2.2	2.1	6.5	6.4
Interest cost	80.0	91.4	238.9	276.0
Expected return on assets	(103.1)	(111.8)	(308.0)	(337.4)
Amortization of prior service (benefit) cost	(1.1)	(1.1)	(3.3)	(1.7)
Recognized net actuarial loss	49.2	37.5	147.4	112.8
Curtailment gain				(0.6)
Net periodic benefit expense	27.2	18.1	81.5	55.5
U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Interest cost	56.1	61.6	168.1	186.3
Expected return on assets	(63.7)	(71.3)	(191.1)	(215.3)
Amortization of prior service (benefit) cost	(0.6)	(0.5)	(1.8)	(0.1)
Recognized net actuarial loss	33.1	27.5	99.5	82.3
Net periodic benefit expense	24.9	17.3	74.7	53.2
International Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	2.2	2.1	6.5	6.4
Interest cost	23.9	29.8	70.8	89.7
Expected return on assets	(39.4)	(40.5)	(116.9)	(122.1)
Amortization of prior service (benefit) cost	(0.5)	(0.6)	(1.5)	(1.6)
Recognized net actuarial loss	16.1	10.0	47.9	30.5
Curtailment gain				(0.6)
Net periodic benefit expense	$ 2.3	$ 0.8	$ 6.8	$ 2.3