Consolidated Balance Sheets (Unaudited) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012		Dec. 31, 2011	Mar. 31, 2011
Assets
Cash and due from banks	$ 691,697		$ 976,191	$ 805,928
Funds sold and resell agreements	14,609		10,174	2,462
Trading securities	128,376		76,800	80,719
Investment securities (fair value : Mar. 31, 2012 - $451,443; December 31, 2011 - $462,657; Mar. 31, 2011 - $355,052)	427,259		439,236	343,401
Available for sale securities	10,186,597		10,179,365	9,665,901
Fair value option securities	347,952		651,226	326,624
Residential mortgage loans held for sale	247,039		188,125	127,119
Loans	11,577,444		11,269,743	10,589,835
Less allowance for loan losses	(244,209)		(253,481)	(289,549)
Loans, net of allowance	11,333,235		11,016,262	10,300,286
Premises and equipment, net	263,579		262,735	265,532
Receivables	138,325		123,257	113,060
Goodwill	335,601		335,601	335,601
Intangible assets, net	9,645		10,219	12,906
Mortgage servicing rights, net	98,138		86,783	120,345
Real estate and other repossessed assets	115,790		122,753	131,420
Bankers' acceptances	3,493		1,881	1,884
Derivative contracts	384,996	[1]	293,859	245,124
Cash surrender value of bank-owned life insurance	266,227		263,318	258,322
Receivable on unsettled securities trades	511,288		75,151	242,828
Other assets	380,327		381,010	321,561
Total assets	25,884,173		25,493,946	23,701,023
Noninterest-bearing demand deposits	6,189,172		5,799,785	4,457,187
Interest-bearing deposits:
Transaction	8,908,397		9,354,456	9,528,864
Savings	259,619		226,357	209,264
Time	3,166,099		3,381,982	3,677,611
Total deposits	18,523,287		18,762,580	17,872,926
Funds purchased	1,784,940		1,063,318	466,749
Repurchase agreements	1,162,546		1,233,064	1,006,051
Other borrowings	209,230		74,485	36,864
Subordinated debentures	394,760		398,881	398,744
Accrued interest, taxes and expense	180,840		149,508	135,486
Bankers' acceptances	3,493		1,881	1,884
Due on unsettled securities trades	305,166		653,371	843,904
Derivative contracts, liabilities	305,290	[1]	236,522	156,038
Other liabilities	144,220		133,684	184,689
Total liabilities	23,013,772		22,707,294	21,103,335
Shareholders' equity:
Common stock ($.00006 par value; 2,500,000,000 shares authorized; shares issued and outstanding: Mar. 31, 2012 - 71,902,099; December 31, 2011 - 71,533,354; Mar. 31, 2011 - 71,073,780)	4		4	4
Capital surplus	829,991		818,817	790,852
Retained earnings	2,014,599		1,953,332	1,791,698
Treasury stock (shares at cost: Mar. 31, 2012 - 3,785,206; December 31, 2011 - 3,380,310; Mar. 31, 2011 - 2,635,358)	(171,593)		(150,664)	(114,734)
Accumulated other comprehensive income	161,418		128,979	108,313
Total shareholders' equity	2,834,419		2,750,468	2,576,133
Non-controlling interest	35,982		36,184	21,555
Total equity	2,870,401		2,786,652	2,597,688
Total liabilities and equity	$ 25,884,173		$ 25,493,964	$ 23,701,023

[1] Derivative contracts are recorded on a net basis in the balance sheet in recognition of master netting agreements that enable the Company to settle all derivative positions with a given counterparty in total and to offset the net derivative position with the related cash collateral.