v2.4.0.6
Available-For-Sale Securities (Summary Of Available-For-Sale Debt And Equity Securities At Estimated Fair Value) (Details) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2012
Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost, Total $ 569,748 $ 9,109,173
Gross Unrealized Gains 0 7,052
Gross Unrealized Losses 3,332 35,076
Estimated Fair Value, Debt securities 566,416 9,072,646
Estimated Fair Value, Equity securities 0 8,503
Estimated Fair Value, Total 566,416 9,081,149
Money Market Funds [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost, Debt securities 518,248 7,455,982
Gross Unrealized Gains 0 0
Gross Unrealized Losses 0 0
Estimated Fair Value, Debt securities 518,248 7,455,982
Certificates of Deposit [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost, Debt securities 0 1,140,000
Gross Unrealized Gains 0 0
Gross Unrealized Losses 0 18
Estimated Fair Value, Debt securities 0 1,139,982
Non-U.S. Government Securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost, Debt securities 0 55,246
Gross Unrealized Gains 0 0
Gross Unrealized Losses 0 30,505
Estimated Fair Value, Debt securities 0 24,741
Corporate Debt Securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost, Debt securities 0 404,994
Gross Unrealized Gains 0 0
Gross Unrealized Losses 0 5
Estimated Fair Value, Debt securities 0 404,989
Student Loan-Backed Securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost, Debt securities 51,500 51,500
Gross Unrealized Gains 0 0
Gross Unrealized Losses 3,332 4,548
Estimated Fair Value, Debt securities 48,168 46,952
Debt Securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost, Debt securities 569,748 9,107,722
Gross Unrealized Gains 0 0
Gross Unrealized Losses 3,332 35,076
Estimated Fair Value, Debt securities 566,416 9,072,646
Equity Securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost, Equity securities 0 1,451
Gross Unrealized Gains 0 7,052
Gross Unrealized Losses 0 0
Estimated Fair Value, Equity securities $ 0 $ 8,503