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	Sep. 30, 2014	Dec. 31, 2013
Investments, Debt and Equity Securities [Abstract]
Amortized Cost, Due in one year or less	$ 889,062
Amortized Cost, Due after one year through five years	4,052,836
Amortized Cost, Due after five years through ten years	3,105,077
Amortized Cost, Due after ten years	2,523,971
Amortized Cost, Mortgaged-backed securities	1,310,361
Total investments in fixed maturity securities, Amortized Value	11,881,307	11,291,631
Fair Value, Due in one year or less	900,273
Fair Value, Due after one year through five years	4,268,705
Fair Value, Due after five years through ten years	3,288,731
Fair Value, Due after ten years	2,634,261
Fair Value, Mortgage-backed securities	1,326,046
Total investments in fixed maturity securities, Fair Value	$ 12,418,016	$ 11,631,744