Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
OPERATING ACTIVITIES:
Net income	$ 271,439	$ 259,623	$ 221,875
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	27,287	51,515	100,000
Provision for depreciation and amortization	43,448	46,743	48,924
Amortization of investment security premiums, net	36,238	18,972	21,635
Deferred income tax (benefit) expense	16,234	(2,836)	(9,085)
Investment securities (gains) losses, net	(4,828)	(10,812)	1,785
Gain on sale of held to maturity student loans	0	0	(6,914)
Net gains on sales of loans held for sale	(376)	(2,040)	(10,402)
Proceeds from sales of loans held for sale	22,720	87,732	635,743
Originations of loans held for sale	0	(52,995)	(344,360)
Net (increase) decrease in trading securities	(9,645)	2,354	(928)
Stock-based compensation	5,001	4,731	6,021
(Increase) decrease in interest receivable	3,149	(2,010)	12,041
Decrease in interest payable	(1,272)	(4,598)	(9,462)
Increase (decrease) in income taxes payable	(13,395)	14,519	2,714
Net tax benefit related to equity compensation plans	(2,094)	(1,065)	(1,178)
Other changes, net	(10,794)	(2,472)	2,768
Net cash provided by operating activities	383,112	407,361	671,177
INVESTING ACTIVITIES
Proceeds from sales of available for sale securities	16,875	19,833	78,640
Proceeds from maturities/pay downs of available for sale securities	3,080,664	2,562,551	2,308,323
Purchases of available for sale securities	(3,182,857)	(4,517,463)	(3,217,600)
Net (increase) decrease in loans	(693,193)	168,983	644,314
Long-term securities purchased under agreements to resell	(575,000)	(500,000)	(450,000)
Repayments of long-term securities purchased under agreements to resell	225,000	100,000	0
Purchases of land, buildings and equipment	(34,969)	(21,332)	(18,528)
Sales of land, buildings and equipment	2,643	2,593	397
Net cash used in investing activities	(1,160,837)	(2,184,835)	(654,454)
FINANCING ACTIVITIES
Net increase in non-interest bearing, savings, interest checking and money market deposits	1,777,058	1,981,201	1,300,555
Net decrease in time open and C.D.’s	(257,586)	(255,769)	(469,557)
Long-term securities sold under agreements to repurchase	0	0	400,000
Repayment of long-term securities sold under agreements to repurchase	0	0	(500,000)
Net increase (decrease) in short-term federal funds purchased and securities sold under agreements to repurchase	(172,531)	273,254	(20,364)
Repayment of other long-term borrowings	(8,107)	(456)	(623,789)
Purchases of treasury stock	(104,909)	(101,154)	(40,984)
Issuance of stock under stock purchase and equity compensation plans	15,588	15,349	11,310
Net tax benefit related to equity compensation plans	2,094	1,065	1,178
Cash dividends paid on common stock	(211,608)	(79,140)	(78,231)
Net cash provided by (used in) financing activities	1,039,999	1,834,350	(19,882)
Increase (decrease) in cash and cash equivalents	262,274	56,876	(3,159)
Cash and cash equivalents at beginning of year	517,551	460,675	463,834
Cash and cash equivalents at end of year	779,825	517,551	460,675
Supplemental Cash Flow Information:
Income tax payments, net	119,166	106,653	100,610
Interest paid on deposits and borrowings	39,335	56,499	93,008
Loans transferred to foreclosed real estate	$ 8,167	$ 22,957	$ 16,440