Securities In An Unrealized Loss Position Non-Investment Grade Fixed Maturity Securities (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Aggregate fair value of securities in a continuous unrealized loss position	$ 2,883,593	$ 3,441,075
Mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Aggregate fair value of securities in a continuous unrealized loss position	641,977	719,251
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Aggregate fair value of securities in a continuous unrealized loss position	1,102,263	1,118,447
State and municipal
Schedule of Available-for-sale Securities [Line Items]
Aggregate fair value of securities in a continuous unrealized loss position	511,542	986,958
Foreign government
Schedule of Available-for-sale Securities [Line Items]
Aggregate fair value of securities in a continuous unrealized loss position	292,025	320,215
Noninvestment Grade Investments at Loss Less than 5 Million
Schedule of Available-for-sale Securities [Line Items]
Number of Securities	20
Aggregate fair value of securities in a continuous unrealized loss position	79,477
Gross Unrealized Loss	5,658
Noninvestment Grade Investments at Loss Less than 5 Million | Mortgage-backed securities
Schedule of Available-for-sale Securities [Line Items]
Number of Securities	9
Aggregate fair value of securities in a continuous unrealized loss position	40,109
Gross Unrealized Loss	2,512
Noninvestment Grade Investments at Loss Less than 5 Million | Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of Securities	8
Aggregate fair value of securities in a continuous unrealized loss position	18,090
Gross Unrealized Loss	803
Noninvestment Grade Investments at Loss Less than 5 Million | Foreign government
Schedule of Available-for-sale Securities [Line Items]
Number of Securities	3
Aggregate fair value of securities in a continuous unrealized loss position	21,278
Gross Unrealized Loss	$ 2,343