Components of Net Periodic Benefit Expense (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Other Postretirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0.2	$ 0.1	$ 0.3	$ 0.3
Interest cost	1.7	2.0	3.4	4.0
Expected return on assets	(0.1)	(0.2)	(0.2)	(0.3)
Amortization of prior service cost	0.3	0.5	0.6	0.9
Recognized net actuarial loss	0.7	0.9	1.4	1.7
Net periodic pension expense	2.8	3.3	5.5	6.6
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	2.1	1.9	4.3	4.3
Interest cost	79.0	92.3	158.9	184.6
Expected return on assets	(102.2)	(112.9)	(204.9)	(225.6)
Amortization of prior service cost	(1.1)	(0.3)	(2.2)	(0.6)
Recognized net actuarial loss	48.6	37.5	98.2	75.3
Curtailment gain		(0.6)		(0.6)
Net periodic pension expense	26.4	17.9	54.3	37.4
U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Interest cost	55.9	62.2	112.0	124.7
Expected return on assets	(63.7)	(72.0)	(127.4)	(144.0)
Amortization of prior service cost	(0.6)	0.2	(1.2)	0.4
Recognized net actuarial loss	32.7	27.0	66.4	54.8
Net periodic pension expense	24.3	17.4	49.8	35.9
International Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	2.1	1.9	4.3	4.3
Interest cost	23.1	30.1	46.9	59.9
Expected return on assets	(38.5)	(40.9)	(77.5)	(81.6)
Amortization of prior service cost	(0.5)	(0.5)	(1.0)	(1.0)
Recognized net actuarial loss	15.9	10.5	31.8	20.5
Curtailment gain		(0.6)		(0.6)
Net periodic pension expense	$ 2.1	$ 0.5	$ 4.5	$ 1.5