CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (USD $) In Thousands	Total	Parent [Member]	Preferred shares [Member]	Common shares (par value) [Member]	Additional paid-in capital [Member]	Unrealized appreciation on available for sale investments, net of tax [Member]	Cumulative foreign currency translation adjustments, net of tax [Member]	Supplemental Executive Retirement Plans (SERPs) [Member]	Accumulated other comprehensive income [Member]	Retained earnings [Member]	Treasury shares, at cost [Member]	Noncontrolling interest [Member]
Total shareholders' equity at Dec. 31, 2010			$ 500,000	$ 1,934	$ 2,059,708	$ 161,802	$ 16,829	$ (1,810)	$ 176,821	$ 4,267,608	$ (1,381,101)
Shares issued			0	191	1,769
Treasury shares reissued					0						0
Issue costs on newly issued preferred shares					0
Value of shares repurchased and retired during the period			0		0					0
Stock options exercised					4,775
Share-based compensation expense					39,134
Unrealized gains (losses) arising during the period, net of reclassification adjustment	(45,251)					(45,251)
Non-credit portion of OTTI losses	(455)					(455)
Foreign currency translation adjustment	(3,045)						(3,045)
Net change in benefit plan assets and obligations recognized in equity	92							92
Net income	46,305									46,305
Preferred share dividends										(36,875)
Common share dividends										(121,646)
Shares repurchased for treasury											(65,885)
Total shareholders' equity at Dec. 31, 2011	5,444,079	5,444,079	500,000	2,125	2,105,386	116,096	13,784	(1,718)	128,162	4,155,392	(1,446,986)	0
Shares issued			400,000	21	2,582
Treasury shares reissued					0						0
Issue costs on newly issued preferred shares					(6,456)
Value of shares repurchased and retired during the period			(397,157)		7,093					(14,009)
Stock options exercised					2,517
Share-based compensation expense					67,912
Unrealized gains (losses) arising during the period, net of reclassification adjustment	232,232					232,232
Non-credit portion of OTTI losses	0					0
Foreign currency translation adjustment	510						510
Net change in benefit plan assets and obligations recognized in equity	1,718							1,718
Net income	547,241									547,241
Preferred share dividends										(38,228)
Common share dividends										(152,607)
Shares repurchased for treasury											(317,687)
Total shareholders' equity at Dec. 31, 2012	5,779,761	5,779,761	502,843	2,146	2,179,034	348,328	14,294	0	362,622	4,497,789	(1,764,673)	0
Shares issued			225,000	28	3,422
Treasury shares reissued					(4,225)						4,225
Issue costs on newly issued preferred shares					(6,551)
Value of shares repurchased and retired during the period			(100,000)		3,081					(3,081)
Stock options exercised					16,889
Share-based compensation expense					48,475
Unrealized gains (losses) arising during the period, net of reclassification adjustment	(223,383)					(223,383)
Non-credit portion of OTTI losses	0					0
Foreign currency translation adjustment	(21,414)						(21,414)
Net change in benefit plan assets and obligations recognized in equity	0							0
Net income	727,465									727,465
Preferred share dividends										(40,474)
Common share dividends										(118,993)
Shares repurchased for treasury											(472,263)
Total shareholders' equity at Dec. 31, 2013	$ 5,867,962	$ 5,817,962	$ 627,843	$ 2,174	$ 2,240,125	$ 124,945	$ (7,120)	$ 0	$ 117,825	$ 5,062,706	$ (2,232,711)	$ 50,000