Income Taxes - Schedule of Components of Net Deferred Tax Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Accruals not currently deductible for tax purposes	$ 199.7	$ 285.8
Inventory	44.3	83.9
Postretirement and pension liabilities	71.7	149.8
Net operating losses	376.4	361.3
Foreign tax credits	7.5	34.0
Other	145.0	193.0
Total gross deferred tax assets	873.6	1,151.8
Less valuation allowance	(294.8)	(325.3)
Net deferred tax assets after valuation allowance	578.8	826.5
Deferred tax liabilities:
Accelerated depreciation	(108.3)	(159.5)
Amortizable intangibles	(3,572.2)	(5,300.5)
Other	(35.8)	(35.0)
Total gross deferred tax liabilities	(3,734.6)	(5,814.0)
Outside Basis DIfferences [Member]
Deferred tax liabilities:
Other	(18.3)	(319.0)
Postretirement Liabilities [Member]
Deferred tax assets:
Postretirement and pension liabilities	29.0	44.0
Balance Sheet Item [Member]
Deferred tax liabilities:
Net deferred tax liabilities	$ (3,155.8)	$ (4,987.5)