Components of Income Before Income Taxes (Detail) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Schedule of Income Before Income Tax [Line Items]
United States									$ 1,291,800,000	$ 435,100,000	$ 425,100,000
Foreign									(78,400,000)	297,300,000	85,700,000
Income from operations before income taxes	$ 1,102,700,000	$ 119,000,000	$ (135,900,000)	$ 127,600,000	$ 177,300,000	$ 178,200,000	$ 185,500,000	$ 191,400,000	$ 1,213,400,000	$ 732,400,000	$ 510,800,000