Debt - Additional Information (Detail)	9 Months Ended		1 Months Ended	9 Months Ended	1 Months Ended
	Sep. 30, 2014 USD ($)	Sep. 30, 2013 USD ($)	Apr. 30, 2014 Senior Subordinated Notes USD ($)	Sep. 30, 2014 Senior Subordinated Notes USD ($)	Mar. 31, 2014 Senior Subordinated Convertible Notes USD ($) D	Jul. 31, 2014 Three Point Seven Five Percent Senior Notes Due October Two Thousand Twenty One USD ($)	Jul. 31, 2014 Three Point Seven Five Percent Senior Notes Due October Two Thousand Twenty One EUR (€)
Debt Instrument [Line Items]
Private offering senior notes, aggregate principal amount							€ 300,000,000
Interest rate of debt instrument					1.125%		3.75%
Senior notes, maturity period						2021-10
Net proceeds from issuance of senior notes after deducting fees and expenses						400,000,000
Debt instrument aggregate principal amount repurchased consideration			523,000,000
Loss on the extinguishment of debt	54,400,000	25,900,000		54,400,000
Private offering senior subordinated convertible notes, aggregate principal amount					690,000,000
Debt instrument maturity year					2034
Net proceeds after deducting fees and expenses					674,000,000
Initial conversion rate for common stock					13.36
Convertible note, initial conversion price per share					$ 74.86
Principal amount of convertible notes in to shares common stock					1,000
Percentage by which closing sale price of common stock is more than the current conversion price					130.00%
Number of trading days					20
Number of Consecutive trading days					30 days
Number Of Trading Days					60 days
Number of consecutive trading days immediately preceding, but excluding, declaration date					10 days
Percentage that distribution has per share value exceeding closing sale price of common stock					10.00%
Percentage of closing sale price of common stock in excess of convertible notes trading price					98.00%
Trading-day period					10 days
Convertible Debt Initial Liability Component					471,000,000
Convertible Debt Equity Component					$ 219,000,000
Effective interest rate					5.50%