Components of Change in Projected Benefit Obligation and Change in Plan Assets (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Change in projected benefit obligation:
Benefit obligation, beginning balance	$ 2,417.4	$ 1,961.6
Service cost	91.3	67.3	$ 73.5
Interest cost	92.2	91.8	81.0
Benefits paid	(121.3)	(72.5)
Actuarial (gain) loss	(141.6)	412.8
Currency translation and other	(35.6)	(47.6)
Participant contributions	3.6	4.0
Projected benefit obligation, ending balance	2,306.0	2,417.4	1,961.6
Change in plan assets:
Fair value of plan assets, beginning balance	2,309.4	2,108.4
Employer contributions	62.9	81.1
Actual return on plan assets	0.3	235.8
Benefits paid	(121.3)	(72.5)
Currency translation and other	(35.9)	(47.4)
Participant contributions	3.6	4.0
Fair value of plan assets, ending balance	2,219.0	2,309.4	$ 2,108.4
Funded status, ending balance	(87.0)	(108.0)
Amounts recorded on balance sheet
Other noncurrent assets	27.2	15.0
Other liabilities	114.2	123.0
Accumulated other comprehensive loss:
Actuarial loss	386.3	428.9
Prior service cost	3.9	3.9
Net initial transition amount	$ 0.2	$ 0.3