Acquisitions, Investments and Dispositions - Income from Discontinued Operations (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Pre-tax income from discontinued operations	$ 4.6	$ 18.4	$ 46.5	$ 57.9
Discontinued operations, net of income taxes	2.8	11.2	28.5	35.2
Harrah's St. Louis Casino [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net revenues	60.8	64.3	189.3	194.6
Pre-tax income from discontinued operations	4.6	18.4	46.5	57.9
Discontinued operations, net of income taxes	$ 2.8	$ 11.2	$ 28.5	$ 35.2