Net Deferred Tax Liabilities (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Schedule of Deferred Income Tax Assets and Liabilities
Property and equipment	$ 1,812.4	$ 1,713.9
Other	639.8	636.4
Total deferred tax liabilities	2,452.2	2,350.3
Property and equipment	(407.9)	(403.6)
Employee benefit plans	(388.9)	(362.9)
Intangible assets	(210.1)	(258.0)
Deferred foreign tax credits	(192.3)	(179.5)
Operating loss carryforwards	(154.0)	(92.4)
Other	(347.6)	(319.4)
Total deferred tax assets before valuation allowance	(1,700.8)	(1,615.8)
Valuation allowance	172.8	127.0
Net deferred tax liabilities	924.2	861.5
Balance sheet presentation: [Abstract]
Deferred income taxes	1,647.7	1,531.1
Other noncurrent assets
Balance sheet presentation: [Abstract]
Deferred tax assets	(621.4)	(603.6)
Prepaid expenses and other current assets
Balance sheet presentation: [Abstract]
Deferred tax assets	$ (102.1)	$ (66.0)