Investments (Components Of Realized Gains And Losses) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Gain (Loss) on Investments [Line Items]
Gross realized gains on sale of invested assets	$ 55,714	$ 58,223	$ 118,006	$ 102,472
Gross realized losses on sale of invested assets	(4,025)	(35,077)	(16,273)	(42,042)
Net realized and unrealized losses on derivatives	(13,720)	8,538	(26,640)	7,561
Net realized investment gains	85,217	(115,198)	139,422	(35,561)
Debt Securities [Member]
Gain (Loss) on Investments [Line Items]
Mark-to-market changes	36,426	(115,113)	58,882	(131,588)
Equity securities [Member]
Gain (Loss) on Investments [Line Items]
Mark-to-market changes	21,316	(34,330)	(289)	(1,357)
Other invested assets [Member]
Gain (Loss) on Investments [Line Items]
Mark-to-market changes	$ (10,494)	$ 2,561	$ 5,736	$ 29,393