Condensed Consolidated Statements of Shareholders' Equity (USD $) In Thousands	Total	[CommonStockMember]	[PreferredStockMember]	[AdditionalPaidInCapitalMember]	[AccumulatedOtherComprehensiveIncomeMember]	[AccumulatedOtherComprehensiveIncomeMember] [CurrencyTranslationAdjustmentMember]	[AccumulatedOtherComprehensiveIncomeMember] [UnfundedPensionObligationMember]	[AccumulatedOtherComprehensiveIncomeMember] [UnrealizedGainsLossesOnInvestmentsMember]	[RetainedEarningsMember]	[TreasuryStockMember]	[NoncontrollingInterestMember]
Balance at beginning of period at Dec. 31, 2011		$ 84,767	$ 35,750	$ 3,803,796	$ (12,644)	$ 4,267	$ (23,076)	$ 6,165	$ 4,035,103	$ (1,479,230)
Net income	1,022,994								1,022,994
Net income attributable to noncontrollong interests	0								0
Dividends on common shares									(118,152)
Dividends on preferred shares	(46,216)								(46,216)
Loss on redemption of preferred shares	0								0
Issuance of common shares		437		36,845
Issuance of preferred shares			0	0
Redemption of preferred shares			0	0
Change in currency translation adjustment	31,042					31,042
Change in unfunded pension obligation, net of tax	(165)						(165)
Change in unrealized losses on investments	(718)							(718)
Repurchase of common shares										(314,607)
Noncontrolling interests											0
Total shareholders' equity	7,079,002
Balance at end of period at Sep. 30, 2012	7,079,002	85,204	35,750	3,840,641	17,515	35,309	(23,241)	5,447	4,893,729	(1,793,837)
Balance at beginning of period at Jun. 30, 2012
Net income	486,706
Net income attributable to noncontrollong interests	0
Dividends on preferred shares	(15,405)
Loss on redemption of preferred shares	0
Change in currency translation adjustment	32,992
Change in unfunded pension obligation, net of tax	(590)
Change in unrealized losses on investments	(237)
Noncontrolling interests											0
Total shareholders' equity	7,079,002
Balance at end of period at Sep. 30, 2012	7,079,002				17,515
Balance at beginning of period at Dec. 31, 2012	6,933,496	85,460	35,750	3,861,844	10,597	32,755	(27,370)	5,212	4,952,002	(2,012,157)
Net income	397,517								397,517
Net income attributable to noncontrollong interests	5,296								(5,296)
Dividends on common shares									(108,191)
Dividends on preferred shares	(43,678)								(43,678)
Loss on redemption of preferred shares	(9,135)								(9,135)
Issuance of common shares		966		56,568
Issuance of preferred shares			10,000	231,265
Redemption of preferred shares			(11,600)	(269,265)
Change in currency translation adjustment	(16,912)					(16,912)
Change in unfunded pension obligation, net of tax	980						980
Change in unrealized losses on investments	(692)							(692)
Repurchase of common shares										(594,336)
Noncontrolling interests	52,489										52,489
Total shareholders' equity	6,624,176
Balance at end of period at Sep. 30, 2013	6,571,687	86,426	34,150	3,880,412	(6,027)	15,843	(26,390)	4,520	5,183,219	(2,606,493)
Balance at beginning of period at Jun. 30, 2013
Net income	337,535
Net income attributable to noncontrollong interests	4,112
Dividends on preferred shares	(14,184)
Loss on redemption of preferred shares	0
Change in currency translation adjustment	14,432
Change in unfunded pension obligation, net of tax	114
Change in unrealized losses on investments	(229)
Noncontrolling interests	52,489										52,489
Total shareholders' equity	6,624,176
Balance at end of period at Sep. 30, 2013	$ 6,571,687				$ (6,027)