CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Comprehensive income
Net income	$ 631,893,000	$ 546,045,000	$ 535,742,000
Other comprehensive income (loss):
Change in foreign currency translation adjustments	37,680,000	(25,500,000)	51,320,000
Change in unrealized gain (loss) on securities	451,905,000	769,105,000	542,911,000
Change in other-than-temporary impairment losses recognized in other comprehensive income	6,434,000	(1,236,000)	4,081,000
Changes in pension and other postretirement plan adjustments	(5,270,000)	(16,400,000)	1,566,000
Total other comprehensive income (loss)	490,749,000	725,969,000	599,878,000
Total comprehensive income (loss)	$ 1,122,642,000	$ 1,272,014,000	$ 1,135,620,000