Annual report pursuant to Section 13 and 15(d)

Available-for-Sale Securities, at Fair Value Schedule of Realized Gain (Loss) (Details)

v2.4.0.6
Available-for-Sale Securities, at Fair Value Schedule of Realized Gain (Loss) (Details) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Schedule of Available-for-sale Securities [Line Items]      
Available-for-sale Securities, Gross Realized Gains (Losses), Sale Proceeds $ 3,411,580 $ 1,046,628  
Available-for-sale Securities, Gross Realized Gains (Losses), Amortized Cost Sold 3,298,689 1,016,961  
Available-for-sale Securities, Gross Realized Gains 115,750 29,983 6,607
Available-for-sale Securities, Gross Realized Losses (2,859) (316) (332)
Available-for-sale Securities, Gross Realized Gain (Loss) $ 112,891 $ 29,667 $ 6,275