Accumulated Other Comprehensive Income (Summary Of Accumulated Other Comprehensive Income, Net Of Taxes) (Details) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Net unrealized gains on investments	$ 885,490	$ 1,749,757
Net unrealized foreign exchange losses	(2,742)	(3,838)
Accumulated other comprehensive income	824,179	1,687,363
Net Minimum Pension Liability [Member]
Accumulated other comprehensive income (loss) related to defined benefit pension and other postretirement plans, net of tax	(59,706)	(60,177)
Net Postretirement Benefit [Member]
Accumulated other comprehensive income (loss) related to defined benefit pension and other postretirement plans, net of tax	$ 1,137	$ 1,621