Debt (Convertible Senior Subordinated Notes Due) (Narrative) (Details) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	3 Months Ended					3 Months Ended		0 Months Ended		3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014 5.75% Senior Notes Due 2022 [Member]	Dec. 31, 2013 5.75% Senior Notes Due 2022 [Member]	Dec. 19, 2013 5.75% Senior Notes Due 2022 [Member]	Mar. 31, 2014 1.75% Convertible Senior Subordinated Notes Due April 15, 2015 [Member]	Apr. 09, 2008 1.75% Convertible Senior Subordinated Notes Due April 15, 2015 [Member]	Apr. 09, 2008 1.75% Convertible Senior Subordinated Notes Due April 15, 2015 [Member] Call Options Purchased [Member]	Apr. 09, 2008 1.75% Convertible Senior Subordinated Notes Due April 15, 2015 [Member] Warrants [Member]	Mar. 31, 2014 Prepaid Expenses and Other Current Assets [Member] 5.75% Senior Notes Due 2022 [Member]
Subsidiary, Sale of Stock [Line Items]
Principal amount of convertible notes			$ 700,000,000	$ 700,000,000	$ 700,000,000
Notes, interest rate			5.75%	5.75%	5.75%	1.75%
Debt instrument maturity year			2022
Proceeds from issuance of notes			700,000,000
Proceeds from issuance of Term Loans	1,525,000,000	0
Cost paid to investment bankers										12,800,000
Convertible Note Gross						379,500,000
Convertible notes, maturity date						Apr. 15, 2015		Apr. 15, 2015
Initial conversion price						$ 29.20
Share price (usd per share)						$ 37.96
Percent of initial conversion price (percent)						130.00%
Convertible notes, convertible amount per share							$ 24.85	$ 40.00
Convertible notes, conversion premium over the closing price							61.10%
Option to purchase, shares	13.0							13.0	13.0
Call option strike price per share								29.20	40.00
Cost of the call option								107,600,000
Proceeds from issuance of warrants									$ 50,400,000