Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
OPERATING ACTIVITIES:
Net income	$ 64,121	$ 60,808
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	9,660	3,285
Provision for depreciation and amortization	10,508	10,424
Amortization of investment security premiums, net	6,675	12,539
Investment securities gains (losses), net	(10,037)	2,165
Net decrease in trading securities	16,597	9,609
Stock-based compensation	2,261	1,223
(Increase) decrease in interest receivable	(1,421)	(5)
Increase (decrease) in interest payable	25	246
Increase (decrease) in income taxes payable	30,410	26,894
Net tax benefit related to equity compensation plans	(800)	(181)
Other changes, net	(6,524)	(28,936)
Net cash provided by (used in) operating activities	121,475	98,071
INVESTING ACTIVITIES:
Proceeds from sales of investment securities	31,666	52
Proceeds from maturities/pay downs of investment securities	456,956	674,270
Purchases of investment securities	(628,237)	(934,142)
Net (increase) decrease in loans	(275,036)	(159,087)
Long-term securities purchased under agreements to resell	(100,000)	(50,000)
Repayments of long-term securities purchased under agreements to resell	300,000	50,000
Purchases of land, buildings and equipment	(3,954)	(5,867)
Sales of land, buildings and equipment	5	404
Net cash provided by (used in) investing activities	(218,600)	(424,370)
FINANCING ACTIVITIES:
Net increase (decrease) in non-interest bearing, savings, interest checking and money market deposits	(132,858)	(138,419)
Net increase (decrease) in time open and C.D.'s	167,862	310,948
Repayment Of Long Term Securities Sold Under Agreements To Repurchase	(150,000)	0
Net increase in short-term federal funds purchased and securities sold under agreements to repurchase	(269,406)	43,308
Repayment of long-term borrowings	(196)	(927)
Net decrease in other short-term borrowings	(2,000)	0
Purchases of treasury stock	(20,900)	(29,993)
Proceeds from Issuance of Shares under Incentive and Share-based Compensation Plans, Including Stock Options	4,085	2,606
Net tax benefit related to equity compensation plans	800	181
Cash dividends paid on common stock	(21,590)	(20,435)
Net cash provided by (used in) financing activities	(424,203)	167,269
Increase (decrease) in cash and cash equivalents	(521,328)	(159,030)
Cash and cash equivalents at beginning of year	1,269,514	779,825
Cash and cash equivalents at end of period	748,186	620,795
Supplemental Cash Flow Information:
Income tax payments, net	(807)	2,031
Interest paid on deposits and borrowings	6,869	8,156
Loans transferred to foreclosed real estate	$ 836	$ 3,925