Consolidated Statement of Changes in Shareholders' Equity (USD $) In Thousands, unless otherwise specified	Total	Preferred Stock	Common Stock	Common Stock Issuable	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss), Net	Treasury Stock
Beginning Balance at Dec. 31, 2008	$ 6,784,731	$ 567,463	$ 60,198	$ 4,617	$ 2,897,907	$ 5,062,754	$ (736,881)	$ (1,071,327)
Comprehensive income:
Net income	379,891					379,891
Other comprehensive income, net of tax and reclassification adjustments:
Unrealized gains on investment securities	337,043						337,043
Defined benefit plans liability adjustment	57,284						57,284
Unrealized gains (losses) on terminated cash flow hedges	6,557						6,557
Total Comprehensive Income	780,775
Acquisition of companies
Preferred stock issued	155,779	155,779
Common stock options	1,367				1,367
Common stock warrants	6,467				6,467
Issuance of common stock to defined benefit pension plan	44,289				(51,417)			95,706
Common stock issued - acquisition	272,824				(348,080)			620,904
Preferred stock cash dividends	(31,946)					(31,946)
Amortization of preferred stock discount		6,993				(6,993)
Repayment of management stock ownership program receivable	195				195
Stock-based compensation plans:
Compensation expense, net	53,505				(21,773)			75,278
Exercises of stock options, net	10,234				(39,936)			50,170
Directors' stock plan	1,251				(1,280)			2,531
Deferred compensation plans, net, including dividend equivalents	53			(275)	(503)	(205)		1,036
Common stock cash dividends - $2.80 per share in 2009, 2010 and 2011	(326,617)					(326,617)
Ending Balance at Dec. 31, 2009	7,752,907	730,235	60,198	4,342	2,442,947	5,076,884	(335,997)	(225,702)
Comprehensive income:
Net income	736,161					736,161
Other comprehensive income, net of tax and reclassification adjustments:
Unrealized gains on investment securities	134,904						134,904
Defined benefit plans liability adjustment	(3,846)						(3,846)
Unrealized gains (losses) on terminated cash flow hedges	(281)						(281)
Total Comprehensive Income	866,938
Acquisition of companies
Preferred stock cash dividends	(40,225)					(40,225)
Amortization of preferred stock discount		10,422				(10,422)
Repayment of management stock ownership program receivable	3,783				3,783
Stock-based compensation plans:
Compensation expense, net	48,576				5,491			43,085
Exercises of stock options, net	49,326				(46,248)			95,574
Directors' stock plan	1,117				(362)			1,479
Deferred compensation plans, net, including dividend equivalents	(14)			(153)	(305)	(195)		639
Stock purchase plan	8,998				(8,482)			17,480
Other	1,791				1,791
Common stock cash dividends - $2.80 per share in 2009, 2010 and 2011	(335,502)					(335,502)
Ending Balance at Dec. 31, 2010	8,357,695	740,657	60,198	4,189	2,398,615	5,426,701	(205,220)	(67,445)
Comprehensive income:
Net income	859,479					859,479
Other comprehensive income, net of tax and reclassification adjustments:
Unrealized gains on investment securities	6,687						6,687
Defined benefit plans liability adjustment	(156,824)						(156,824)
Unrealized gains (losses) on terminated cash flow hedges	(281)						(281)
Foreign currency translation adjustment	(803)						(803)
Total Comprehensive Income	708,258
Acquisition of companies
Common stock issued - acquisition	405,557		2,348		403,209
Partial redemption of Series A preferred stock	(370,000)	(370,000)
Conversion of Series B preferred stock into 433,144 shares of common stock		(26,500)	192		21,754			4,554
Issuance of Series D preferred stock	495,000	500,000			(5,000)
Preferred stock cash dividends	(48,203)					(48,203)
Amortization of preferred stock discount		20,428				(20,428)
Repayment of management stock ownership program receivable	0				0
Stock-based compensation plans:
Compensation expense, net	43,912		50		12,196			31,666
Exercises of stock options, net	25,854		48		(4,300)			30,106
Directors' stock plan	1,431		6		813			612
Deferred compensation plans, net, including dividend equivalents	38			(117)	(164)	(188)		507
Stock purchase plan	0				0			0
Other	1,863				1,863
Common stock cash dividends - $2.80 per share in 2009, 2010 and 2011	(350,196)					(350,196)
Ending Balance at Dec. 31, 2011	$ 9,271,209	$ 864,585	$ 62,842	$ 4,072	$ 2,828,986	$ 5,867,165	$ (356,441)	$ 0