Debt (Cash Convertible Notes) (Narrative) (Details) (USD $)	9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Sep. 15, 2008
Debt Instrument [Line Items]
Long-term debt	$ 5,779,441,000	$ 5,431,948,000
Cash Convertible Notes
Debt Instrument [Line Items]
Trading days	20 days
Consecutive trading days	30 days
Convertible Debt | Cash Convertible Notes
Debt Instrument [Line Items]
Long-term debt	1,597,179,000	1,136,768,000
Debt	518,300,000	500,500,000
Face amount of debt	574,000,000	575,000,000	575,000,000
Discount on debt	55,700,000	74,500,000
Convertible debt instrument, carrying amount of the equity component	1,080,000,000	636,300,000
Ratio of observed share price to conversion reference price	130.00%
Conversion reference price	$ 13.32
Reference principal amount	1,000
Conversion reference rate, per reference principal amount	75.0751
Call Options | Cash Convertible Notes
Debt Instrument [Line Items]
Convertible debt instrument, fair value of associated derivative transaction	$ 1,080,000,000	$ 636,300,000