Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Cash Flows From Operating Activities:
Net income	$ 168,947	$ 182,654
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	(8,000)	(8,000)
Change in fair value of mortgage servicing rights	(16,973)	4,323
Unrealized (gains) losses from derivatives	6,137	(7,626)
Tax benefit on exercise of stock options	(178)	677
Change in bank-owned life insurance	(5,462)	(5,709)
Stock-based compensation	1,357	4,803
Depreciation and amortization	27,634	24,636
Net amortization of securities discounts and premiums	32,867	47,789
Net realized gains on financial instruments and other assets	(57,782)	(60,122)
Mortgage loans originated for resale	(2,152,353)	(1,588,200)
Proceeds from sale of mortgage loans held for resale	2,201,324	1,569,921
Capitalized mortgage servicing rights	(25,932)	(17,647)
Change in trading and fair value option securities	100,889	251,682
Change in receivables	(23,890)	(9,667)
Change in other assets	38,646	2,838
Change in accrued interest, taxes and expense	(1,001)	(9,074)
Change in other liabilities	(13,407)	7,888
Net cash provided by operating activities	272,823	391,166
Cash Flows From Investing Activities:
Proceeds from maturities or redemptions of investment securities	99,020	43,678
Proceeds from maturities or redemptions of available for sale securities	1,689,165	2,486,198
Purchases of investment securities	(217,160)	(16,971)
Purchases of available for sale securities	(3,173,504)	(4,162,486)
Proceeds from sales of available for sale securities	1,837,970	1,451,551
Change in amount receivable on unsettled securities transactions	28,905	42,275
Loans originated net of principal collected	(130,381)	(327,349)
Net proceeds from (payments on) derivative asset contracts	(229,888)	(119,495)
Proceeds from disposition of assets	53,191	101,550
Purchases of assets	(115,250)	(40,991)
Net cash provided by (used in) investing activities	(157,932)	(542,040)
Cash Flows From Financing Activities:
Net change in demand deposits, transaction deposits and savings accounts	(1,482,810)	(126,351)
Net change in time deposits	(200,020)	(274,032)
Net change in other borrowed funds	1,311,756	229,401
Repayment of subordinated debt	0	(46,882)
Net payments or proceeds on derivative liability contracts	220,024	110,249
Net change in derivative margin accounts	114,958	21,749
Change in amount due on unsettled security transactions	(248,084)	(49,571)
Issuance of common and treasury stock, net	12,879	8,454
Tax benefit on exercise of stock options	178	(677)
Repurchase of common stock	0	(20,558)
Dividends paid	(51,626)	(48,010)
Net cash provided by (used in) financing activities	(322,745)	(196,228)
Net decrease in cash and cash equivalents	(207,854)	(347,102)
Cash and cash equivalents at beginning of period	1,286,239	986,365
Cash and cash equivalents at end of period	1,078,385	639,263
Cash paid for interest	36,615	48,536
Cash paid for taxes	73,527	81,738
Net loans and bank premises transferred to repossessed real estate and other assets	52,967	55,821
Residential mortgage loans guaranteed by U.S. government agencies that became eligible for repurchase during the period	55,938	48,486
Conveyance of other real estate owned guaranteed by U.S. government agencies	$ 22,527	$ 34,247