Debt (Cash Convertible Notes) (Narrative) (Details) (Cash Convertible Notes, USD $)	3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Sep. 15, 2008
Debt Instrument [Line Items]
Trading days	20 days
Consecutive trading days	30 days
Convertible Debt
Debt Instrument [Line Items]
Ratio of observed share price to conversion reference price	130.00%
Conversion reference price	$ 13.32
Outstanding principal	$ 574,000,000	$ 574,000,000	$ 575,000,000
Reference principal amount	$ 1,000
Conversion reference rate, per reference principal amount	75.0751