CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 822,852	$ 72,017	$ 1,069,582	$ 177,521
Other comprehensive (loss) income, net of tax:
Change in unrealized investment gains and losses	95,295	(17,301)	51,212	66,798
Benefit plan adjustments	(7,355)	(1,732)	(8,447)	(5,198)
Foreign currency translation adjustment	(2,947)	(2,490)	(4,571)	(650)
Other comprehensive income (loss), net of tax	84,993	(21,523)	38,194	60,950
Comprehensive income	$ 907,845	$ 50,494	$ 1,107,776	$ 238,471