Fair Value Measurements (Summary Of Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 1,302,367	$ 763,885
Marketable securities	153,380	140,118
Derivatives	16,443	37
Total assets measured at fair value	1,472,190	904,040
Derivatives, Liabilities	5,136	20,083
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	1,302,367	763,885
Marketable securities		89,887
Total assets measured at fair value	1,302,367	853,772
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities	153,380	50,231
Derivatives	16,443	37
Total assets measured at fair value	169,823	50,268
Derivatives, Liabilities	5,136	20,083
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents
Marketable securities
Derivatives
Total assets measured at fair value
Derivatives, Liabilities