Net Deferred Tax Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Schedule of Deferred Income Tax Assets and Liabilities
Property and equipment	$ 1,288.9	$ 1,211.5
Intangible liabilities	312.3	296.2
Other	347.9	242.0
Deferred Tax Liabilities, Gross	1,949.1	1,749.7
Property and equipment	(658.9)	(633.8)
Employee benefit plans	(213.3)	(253.1)
Intangible assets	(1,081.5)	(228.8)
Deferred foreign tax credits	(216.6)	(208.6)
Deferred revenue	(138.9)	0.0
Operating loss carryforwards	(45.7)	(71.1)
Other	(269.2)	(266.0)
Total deferred tax assets before valuation allowance	(2,624.1)	(1,661.4)
Valuation allowance	671.1	163.2
Deferred Tax Liabilities, Net	(3.9)	251.5
Balance sheet presentation: [Abstract]
Deferred income taxes	1,215.5	1,119.4
Other assets-miscellaneous
Balance sheet presentation: [Abstract]
Deferred tax assets	$ (1,219.4)	$ (867.9)