Earnings (Losses) Per Share (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Debt
0.94% senior exchangeable notes due 2011, par value outstanding	$ 364,000	$ 275,326,000
Average number of options and warrants excluded from diluted earnings (losses) per share (in shares)	14,200,915	9,241,543	14,004,749
0.94% Senior Exchangeable Notes Due May 2011
Debt
Principal redeemed senior exchangeable notes	1,400,000,000
Interest rate on senior note due (as a percent)	0.94%
0.94% senior exchangeable notes due 2011, par value outstanding	1,400,000,000
Purchase amount of 0.94% senior exchangeable notes due 2011	$ 1,200,000,000