Property and Equipment, net - Property and Equipment, Net (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Property, Plant and Equipment [Line Items]
Land and land improvements	$ 7,400.3	$ 7,411.8
Land concessions	504.4	606.7
Buildings, riverboats, and improvements	8,987.1	8,944.5
Furniture, fixtures, and equipment	2,464.3	2,353.2
Construction in progress	362.9	361.1
Total, Gross	19,719.0	19,677.3
Less: accumulated depreciation	(3,130.4)	(2,607.4)
Property and equipment, net	$ 16,588.6	$ 17,069.9