Property and Equipment, net (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Property, Plant and Equipment [Abstract]
Land and land improvements	$ 7,208.8	$ 7,411.8
Buildings, riverboats, and improvements	8,725.7	8,939.2
Furniture, fixtures, and equipment	2,491.0	2,333.3
Construction in progress	378.3	342.5
Total, Gross	18,803.8	19,026.8
Less: accumulated depreciation	(3,102.1)	(2,541.2)
Property and equipment, net	$ 15,701.7	$ 16,485.6