v2.4.0.6
Fair Value Measurements (Summary Of Assets And Liabilities Recorded At Fair Value) (Details) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2011
Dec. 31, 2010
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities $ 9,072,646 $ 4,944,507
Equity securities 8,503 4,631
Derivatives, assets 100,475 64,461
Fair value assets, total 9,181,624 5,013,599
U.S. Treasury Securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 0 1,355,437
Money Market Funds [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 7,455,982 520,063
Certificates Of Deposit [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 1,139,982 127,619
U.S. Government Agencies And FDIC Guaranteed Securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 0 1,296,110
Municipal Debt Securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 0 17,625
Non-U.S. Government Securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 24,741 288,204
Corporate Debt Securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 404,989 991,635
Residential Mortgage And Asset-Backed Securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 0 277,043
Student Loan-Backed Securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 46,952 70,771
Level 1 [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 7,455,982 1,875,500
Equity securities 8,503 4,631
Derivatives, assets 0 0
Fair value assets, total 7,464,485 1,880,131
Level 1 [Member] | U.S. Treasury Securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 0 1,355,437
Level 1 [Member] | Money Market Funds [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 7,455,982 520,063
Level 1 [Member] | Certificates Of Deposit [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 0 0
Level 1 [Member] | U.S. Government Agencies And FDIC Guaranteed Securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 0 0
Level 1 [Member] | Municipal Debt Securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 0 0
Level 1 [Member] | Non-U.S. Government Securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 0 0
Level 1 [Member] | Corporate Debt Securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 0 0
Level 1 [Member] | Residential Mortgage And Asset-Backed Securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 0 0
Level 1 [Member] | Student Loan-Backed Securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 0 0
Level 2 [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 1,544,971 2,988,642
Equity securities 0 0
Derivatives, assets 100,475 64,461
Fair value assets, total 1,645,446 3,053,103
Level 2 [Member] | U.S. Treasury Securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 0 0
Level 2 [Member] | Money Market Funds [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 0 0
Level 2 [Member] | Certificates Of Deposit [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 1,139,982 127,619
Level 2 [Member] | U.S. Government Agencies And FDIC Guaranteed Securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 0 1,296,110
Level 2 [Member] | Municipal Debt Securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 0 17,625
Level 2 [Member] | Non-U.S. Government Securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 0 278,610
Level 2 [Member] | Corporate Debt Securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 404,989 991,635
Level 2 [Member] | Residential Mortgage And Asset-Backed Securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 0 277,043
Level 2 [Member] | Student Loan-Backed Securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 0 0
Level 3 [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 71,693 80,365
Equity securities 0 0
Derivatives, assets 0 0
Fair value assets, total 71,693 80,365
Level 3 [Member] | U.S. Treasury Securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 0 0
Level 3 [Member] | Money Market Funds [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 0 0
Level 3 [Member] | Certificates Of Deposit [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 0 0
Level 3 [Member] | U.S. Government Agencies And FDIC Guaranteed Securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 0 0
Level 3 [Member] | Municipal Debt Securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 0 0
Level 3 [Member] | Non-U.S. Government Securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 24,741 9,594
Level 3 [Member] | Corporate Debt Securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 0 0
Level 3 [Member] | Residential Mortgage And Asset-Backed Securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 0 0
Level 3 [Member] | Student Loan-Backed Securities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt securities 46,952 70,771
Liabilities [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Contingent consideration 135,591 11,100
Derivatives, liabilities 5,710 38,553
Fair value liabilities, total 141,301 49,653
Liabilities [Member] | Level 1 [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Contingent consideration 0 0
Derivatives, liabilities 0 0
Fair value liabilities, total 0 0
Liabilities [Member] | Level 2 [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Contingent consideration 0 0
Derivatives, liabilities 5,710 38,553
Fair value liabilities, total 5,710 38,553
Liabilities [Member] | Level 3 [Member]
   
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Contingent consideration 135,591 11,100
Derivatives, liabilities 0 0
Fair value liabilities, total $ 135,591 $ 11,100