Quarterly report pursuant to Section 13 or 15(d)

Available-for-Sale Securities, at Fair Value Schedule of Unrealized Loss on Investments (Details)

v2.4.0.8
Available-for-Sale Securities, at Fair Value Schedule of Unrealized Loss on Investments (Details) (USD $)
In Thousands, unless otherwise specified
Sep. 30, 2014
Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]    
Available-for-Sale Securities, Number of Positions 1,423 1,431
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year 89 447
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year 200 114
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value $ 1,409,676 $ 4,902,813
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses (5,261) (171,651)
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value 1,605,423 1,186,692
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses (61,143) (81,393)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value 3,015,099 6,089,505
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses (66,404) (253,044)
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value $ 1,319,217 $ 4,752,861
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Percent Agency 93.60% 96.90%