Investments In Fixed Maturity Securities Investments in Fixed Maturity Securities (Amortized cost and fair value of fixed maturity securities) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Investments, Debt and Equity Securities [Abstract]
Amortized Cost, Due in one year or less	$ 886,256
Amortized Cost, Due after one year through five years	3,860,527
Amortized Cost, Due after five years through ten years	3,035,251
Amortized Cost, Due after ten years	2,492,226
Amortized Cost, Mortgaged-backed securities	1,309,360
Total investments in fixed maturity securities, Amortized Value	11,583,620	11,291,631
Fair Value, Due in one year or less	896,523
Fair Value, Due after one year through five years	4,039,960
Fair Value, Due after five years through ten years	3,229,746
Fair Value, Due after ten years	2,606,741
Fair Value, Mortgage-backed securities	1,334,716
Total investments in fixed maturity securities, Fair Value	$ 12,107,686	$ 11,631,744