Debt (Details 2) (Convertible Notes Due 2016, USD $) In Millions, except Per Share data, unless otherwise specified	9 Months Ended
Sep. 30, 2013
Sale of warrant
Share warrant, number of shares	5.2
Share warrant, exercise price (in dollars per share)	$ 67.56
Purchased call options \| Long
Purchase of call options
Convertible note hedge, approximate number of shares that can be purchased	5.2
Convertible note hedge, exercise price (in dollars per share)	$ 47.69

Exercise price per share or per unit of warrants or rights outstanding.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

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-Subparagraph (SX 210.4-08.(i)(4))

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

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Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

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-Subparagraph (SX 210.4-08.(i)(2))

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

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The number of issuer's shares to which the option contract is indexed.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 40

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The exercise (or strike) price stated in the contract. The fixed price at which the option holder can purchase, in the case of a call option, or sell, in the case of a put option, on the underlying security.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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