Debt (Details) (USD $)	1 Months Ended		1 Months Ended		9 Months Ended
	Sep. 30, 2011	Oct. 13, 2011	Sep. 30, 2011 4.625% Notes due 2016 [Member]	Sep. 30, 2011 5.950% Notes due 2021 [Member]	Oct. 01, 2011 4.50% convertible senior notes due 2013 [Member]	Oct. 13, 2011 4.50% convertible senior notes due 2013 [Member]
Debt (Textual) [Abstract]
Issued Notes			$ 250,000,000	$ 250,000,000
Stated interest rate of Notes Issued			4.625%	5.95%	4.50%
Debt Instrument, Face Amount					600,000,000
Cash tender offer expiration date					Oct. 12, 2011
Terms of Tender Offer, Principal amount of convertible notes purchased						1,000
Terms of Tender Offer, Cash Payment Received for each principal amount of convertible notes purchased						1,524
Terms of tender offer description, amount holder received additionally with cash payment, against each principle amount of convertible notes purchased						plus accrued and unpaid interest
Tender offer settlement date						Oct. 13, 2011
Principal amount of Convertible Notes tendered by holders		225,000,000				225,000,000
Percentage of the convertible notes tendered by holders.		37.50%				37.50%
Cash payment excluding accrued interest for tendered convertible notes						342,000,000
Carrying Value of tendered convertible notes including unamortized issuance costs						200,000,000
Fair Value of liability component of convertible notes purchased in tender offer						234,000,000
Equity component of convertible notes repurchased in cash tender offer						108,000,000
Recognized pretax loss						34,000,000
Reduction To shareholders' equity						108,000,000
Convertible notes, current					200,000,000
Principal amount of convertible notes outstanding after settlement of cash tender offer						375,000,000
Additional Debt (Textual) [Abstract]
Total net proceeds, Debt issued	$ 496,000,000