Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011
OPERATING ACTIVITIES:
Net income	$ 138,050		$ 130,567
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	13,380		27,977
Provision for depreciation and amortization	21,847		23,732
Amortization of investment security premiums, net	16,862		2,413
Investment securities gains, net	(5,376)	[1]	(3,283)	[1]
Net gains on sales of loans held for sale	(375)		(1,147)
Originations of loans held for sale	0		(28,631)
Proceeds from sales of loans held for sale	22,508		51,297
Net increase in trading securities	(4,006)		(374)
Stock-based compensation	2,555		2,372
(Increase) decrease in interest receivable	4,495		(1,095)
Decrease in interest payable	(185)		(2,686)
Increase in income taxes payable	1,999		5,594
Net tax benefit related to equity compensation plans	(744)		(955)
Other changes, net	(7,617)		(10,912)
Net cash provided by operating activities	203,393		194,869
INVESTING ACTIVITIES:
Proceeds from sales of investment securities	14,116	[1]	11,202	[1]
Proceeds from maturities/pay downs of investment securities	1,479,062	[1]	1,400,631	[1]
Purchases of investment securities	(1,477,434)	[1]	(1,809,501)	[1]
Net (increase) decrease in loans	(218,816)		139,927
Long-term securities purchased under agreements to resell	0		(500,000)
Repayments of long-term securities purchased under agreements to resell	0		100,000
Purchases of land, buildings and equipment	(11,703)		(11,133)
Sales of land, buildings and equipment	1,743		1,711
Net cash used in investing activities	(213,032)		(667,163)
FINANCING ACTIVITIES:
Net increase in non-interest bearing, savings, interest checking and money market deposits	335,614		705,923
Net decrease in time open and C.D.'s	(277,223)		(62,335)
Net increase in short-term federal funds purchased and securities sold under agreements to repurchase	49,664		299,643
Repayment of long-term borrowings	(525)		(352)
Net increase in short-term borrowings	0		8
Purchases of treasury stock	(71,652)		(18,341)
Issuance of stock under stock purchase and equity compensation plans	6,785		13,363
Net tax benefit related to equity compensation plans	744		955
Cash dividends paid on common stock	(40,654)		(40,110)
Net cash provided by financing activities	2,753		898,754
Increase (decrease) in cash and cash equivalents	(6,886)		426,460
Cash and cash equivalents at beginning of year	517,551		460,675
Cash and cash equivalents at June 30	510,665		887,135
Supplemental Cash Flow Information:
Income tax payments, net	64,799		54,661
Interest paid on deposits and borrowings	19,933		30,916
Loans transferred to foreclosed real estate	$ 5,488		$ 18,343

[1] Available for sale and non-marketable securities