Annual report pursuant to Section 13 and 15(d)

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

v2.4.1.9
Available-for-Sale Securities, at Fair Value Schedule of Realized Gain (Loss) (Details) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]      
Available-for-sale Securities, Gross Realized Gains (Losses), Sale Proceeds $ 3,479,329us-gaap_AvailableForSaleSecuritiesGrossRealizedGainsLossesSaleProceeds $ 4,432,696us-gaap_AvailableForSaleSecuritiesGrossRealizedGainsLossesSaleProceeds $ 3,411,580us-gaap_AvailableForSaleSecuritiesGrossRealizedGainsLossesSaleProceeds
Available-for-sale Securities, Gross Realized Gains (Losses), Amortized Cost Sold 3,394,914two_AvailableForSaleSecuritiesGrossRealizedGainsLossesAmortizedCostSold 4,497,205two_AvailableForSaleSecuritiesGrossRealizedGainsLossesAmortizedCostSold 3,298,689two_AvailableForSaleSecuritiesGrossRealizedGainsLossesAmortizedCostSold
Available-for-sale Securities, Gross Realized Gains 162,235us-gaap_AvailableForSaleSecuritiesGrossRealizedGains 202,112us-gaap_AvailableForSaleSecuritiesGrossRealizedGains 115,750us-gaap_AvailableForSaleSecuritiesGrossRealizedGains
Available-for-sale Securities, Gross Realized Losses (77,820)us-gaap_AvailableForSaleSecuritiesGrossRealizedLosses (266,620)us-gaap_AvailableForSaleSecuritiesGrossRealizedLosses (2,859)us-gaap_AvailableForSaleSecuritiesGrossRealizedLosses
Available-for-sale Securities, Gross Realized Gain (Loss) $ 84,415us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNet $ (64,508)us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNet $ 112,891us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNet