Equity (Components of Other Comprehensive Income) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss), before Reclassification and Tax		$ 39,925	$ (342,539)	$ (154,132)
Other Comprehensive Income (Loss), Foreign Currency Translation Gain (Loss) Arising During Period, Tax		(24,663)	17,129	(4,835)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax		15,262	(325,410)	(158,967)
Other Comprehensive Income Foreign Currency Transaction And Translation Gain Loss Arising During Period Foreign Currency Swap, Before Reclassification and Tax		(10,234)	96,019	51,894
Other Comprehensive Income Foreign Currency Transaction And Translation Gain Loss Arising During Period Foreign Currency Swap Tax		3,582	(33,607)	(18,163)
Other Comprehensive Income Foreign Currency Transaction And Translation Gain Loss Arising During Period Foreign Currency Swap Net Of Tax		(6,652)	62,412	33,731
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax		29,691	(246,520)	(102,238)
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax		(21,081)	(16,478)	(22,998)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax		8,610	(262,998)	(125,236)
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax	[1]	641,606	(1,084,732)	1,177,017
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax	[1]	(180,448)	359,407	(357,024)
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax	[1]	461,158	(725,325)	819,993
Other Comprehensive Income (Loss), Transfers from Held-to-maturity to Available-for-Sale Securities, before Tax	[1]	65,798	(55,767)	26,405
Other Comprehensive Income (Loss), Transfers from Held-to-maturity to Available-for-Sale Securities, Tax	[1]	(23,029)	19,518	(9,242)
Other Comprehensive Income (Loss), Transfers from Held-to-maturity to Available-for-Sale Securities, Net of Tax	[1]	42,769	(36,249)	17,163
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Reclassification Adjustments and Tax	[1]	575,808	(1,028,965)	1,150,612
Other Comprehensive Income (Loss), Available-for-sale Securities, before Reclassification Adjustments, Tax	[1]	(157,419)	339,889	(347,782)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	[1]	418,389	(689,076)	802,830
Other than Temporary Impairment Loss, Investments, Portion in Other Comprehensive Loss, before Tax, Portion Attributable to Parent, Available-for-sale Securities		1,457		(2,612)
Other than Temporary Impairment Losses, Investments, Portion in Other Comprehensive Loss, Tax, Portion Attributable to Parent, Available-for-sale Securities		(510)		(914)
Other than Temporary Impairment Losses, Investments, Portion in Other Comprehensive Loss, Net of Tax, Portion Attributable to Parent, Available-for-sale Securities		947		1,698
Other Comprehensive (Income) Loss, Amortization Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Prior Service Cost (Credit), before Tax		444	337	485
Other Comprehensive (Income) Loss, Amortization Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Prior Service Cost (Credit), Tax		(149)	(107)	(159)
Other Comprehensive (Income) Loss, Amortization Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Prior Service Cost (Credit), Net of Tax		295	230	326
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), before Tax		4,427	4,618	(43,025)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), Tax		(1,623)	(1,619)	14,929
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), Net of Tax		2,804	2,999	(28,096)
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, before Tax		4,871	4,955	(42,540)
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, Tax		(1,772)	(1,726)	14,770
Defined benefit pension and postretirement plan adjustments		3,099	3,229	(27,770)
Other Comprehensive Income (Loss), before Tax		611,827	(1,270,530)	1,008,446
Other Comprehensive Income (Loss), Tax		(180,782)	321,685	(356,924)
Other Comprehensive Income (Loss), Net of Tax		$ 431,045	$ (948,845)	$ 651,522

[1] Includes cash flow hedges. See Note 5 for additional information on cash flow hedges.