Income Tax (Total Income Taxes Provided) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Effects Allocated Directly to Equity [Abstract]
Income Tax Expense (Benefit)	$ 342,503	$ 242,629	$ 324,486
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax	157,929	(339,889)	348,697
Income Tax Effects Allocated Directly to Equity, Employee Stock Options	(162)	(2,963)	3,011
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	21,081	16,478	22,998
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, Tax	1,772	1,726	(14,770)
Income Tax Expense (Benefit), Intraperiod Tax Allocation	$ 523,123	$ (82,019)	$ 684,422