Consolidated Statements of Changes in Shareholders' Equity (USD $) In Thousands		Total	Non-cumulative preferred shares	Common shares	Additional paid-in capital	Retained earnings	Accumulated other comprehensive income	Unrealized Appreciation on Available-For-Sale Investments	Foreign Currency Translation Adjustments	Common shares held in treasury, at cost
Balance at beginning of year at Dec. 31, 2011			$ 325,000	$ 549	$ 161,419	$ 4,796,655	$ 153,923	$ 174,636	$ (20,713)	$ (845,472)
Shares issued - Series C			325,000
Shares repurchased			(325,000)		10,612	(10,612)
Common shares issued, net				12	6,823
Issue costs on Series C preferred shares					(9,398)
Exercise of stock options					14,218
Amortization of share-based compensation					42,303
Other					1,801
Net income		593,397				593,397
Amounts attributable to noncontrolling interests	[1]	0
Dividends declared on preferred shares		(25,079)				(25,079)
Unrealized holding gains (losses) arising during period, net of reclassification adjustment								116,107
Portion of other-than-temporary impairment losses recognized in other comprehensive income, net of deferred income tax								(787)
Foreign currency translation adjustments		17,774							17,774
Shares repurchased for treasury										(180,367)
Non-redeemable noncontrolling interests	[1]	0
Total shareholders' equity		5,168,878
Balance at end of year at Dec. 31, 2012		5,168,878	325,000	561	227,778	5,354,361	287,017	289,956	(2,939)	(1,025,839)
Shares issued - Series C			0
Shares repurchased			0		0	0
Common shares issued, net				4	8,237
Issue costs on Series C preferred shares					0
Exercise of stock options					10,561
Amortization of share-based compensation					49,237
Other					3,704
Net income		709,731				709,731
Amounts attributable to noncontrolling interests	[1]	0
Dividends declared on preferred shares		(21,938)				(21,938)
Unrealized holding gains (losses) arising during period, net of reclassification adjustment								(209,089)
Portion of other-than-temporary impairment losses recognized in other comprehensive income, net of deferred income tax								(175)
Foreign currency translation adjustments		(2,789)							(2,789)
Shares repurchased for treasury										(68,865)
Non-redeemable noncontrolling interests	[1]	0
Total shareholders' equity		5,647,496
Balance at end of year at Dec. 31, 2013		5,647,496	325,000	565	299,517	6,042,154	74,964	80,692	(5,728)	(1,094,704)
Shares issued - Series C			0
Shares repurchased			0		0	0
Common shares issued, net				7	9,590
Issue costs on Series C preferred shares					0
Exercise of stock options					18,662
Amortization of share-based compensation					54,789
Other					515
Net income		821,260				821,260
Amounts attributable to noncontrolling interests	[1]	13,095
Dividends declared on preferred shares		(21,938)				(21,938)
Unrealized holding gains (losses) arising during period, net of reclassification adjustment								81,226
Portion of other-than-temporary impairment losses recognized in other comprehensive income, net of deferred income tax								(320)
Foreign currency translation adjustments		(27,014)							(27,014)
Shares repurchased for treasury										(467,315)
Non-redeemable noncontrolling interests	[1]	769,081
Total shareholders' equity		6,899,134
Balance at end of year at Dec. 31, 2014		$ 6,130,053	$ 325,000	$ 572	$ 383,073	$ 6,854,571	$ 128,856	$ 161,598	$ (32,742)	$ (1,562,019)

[1] See Note 4.