v2.4.0.6
Investments (Schedule Of Fair Value Of Fixed Maturity Investments Trading) (Details) (USD $)
In Thousands, unless otherwise specified
Jun. 30, 2012
Dec. 31, 2011
Investment [Line Items]    
Fixed maturity investments trading, fair value $ 4,948,955 $ 4,291,465
U.S. treasuries [Member]
   
Investment [Line Items]    
Fixed maturity investments trading, fair value 1,126,759 885,152
Agencies [Member]
   
Investment [Line Items]    
Fixed maturity investments trading, fair value 436,691 158,561
Non-U.S. government (Sovereign Debt) [Member]
   
Investment [Line Items]    
Fixed maturity investments trading, fair value 172,008 216,916
FDIC guaranteed corporate [Member]
   
Investment [Line Items]    
Fixed maturity investments trading, fair value 29,386 423,630
Non-U.S. government-backed corporate [Member]
   
Investment [Line Items]    
Fixed maturity investments trading, fair value 393,875 640,757
Corporate [Member]
   
Investment [Line Items]    
Fixed maturity investments trading, fair value 1,652,007 1,187,437
Agency mortgage-backed [Member]
   
Investment [Line Items]    
Fixed maturity investments trading, fair value 580,971 428,042
Non-agency mortgage-backed [Member]
   
Investment [Line Items]    
Fixed maturity investments trading, fair value 135,268 82,096
Commercial mortgage-backed [Member]
   
Investment [Line Items]    
Fixed maturity investments trading, fair value 414,524 255,885
Asset-backed [Member]
   
Investment [Line Items]    
Fixed maturity investments trading, fair value $ 7,466 $ 12,989