XML 44 R40.htm IDEA: XBRL DOCUMENT v2.4.0.6
Investments (Details 6) (USD $)
Jun. 30, 2012
Dec. 31, 2011
Corporate Secturities by Investment Sector And Credit Rating [Line Items]    
Available For Sale Securities Amortized Cost $ 7,675,473,000 $ 6,931,958,000
Available For Sale Securities Fair Value Disclosure 8,401,909,000 7,461,106,000
Percentage Of Total Available For Sale Securities 100.00% 100.00%
Finance Industry [Member]
   
Corporate Secturities by Investment Sector And Credit Rating [Line Items]    
Available For Sale Securities Amortized Cost 2,618,913,000 2,411,175,000
Available For Sale Securities Fair Value Disclosure 2,762,847,000 2,442,149,000
Percentage Of Total Available For Sale Securities 32.90% 32.70%
Industrial [Member]
   
Corporate Secturities by Investment Sector And Credit Rating [Line Items]    
Available For Sale Securities Amortized Cost 3,834,519,000 3,402,099,000
Available For Sale Securities Fair Value Disclosure 4,257,907,000 3,760,187,000
Percentage Of Total Available For Sale Securities 50.70% 50.40%
Utility Industry [Member]
   
Corporate Secturities by Investment Sector And Credit Rating [Line Items]    
Available For Sale Securities Amortized Cost 1,213,333,000 1,115,384,000
Available For Sale Securities Fair Value Disclosure 1,372,024,000 1,255,090,000
Percentage Of Total Available For Sale Securities 16.30% 16.90%
Other Industry [Member]
   
Corporate Secturities by Investment Sector And Credit Rating [Line Items]    
Available For Sale Securities Amortized Cost 8,708,000 3,300,000
Available For Sale Securities Fair Value Disclosure $ 9,131,000 $ 3,680,000
Percentage Of Total Available For Sale Securities 0.10% 0.00%