Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash Flows From Operating Activities:
Net income	$ 245,009	$ 270,508
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	(16,500)	(8,000)
Change in fair value of mortgage servicing rights	(16,627)	13,899
Unrealized (gains) losses from derivatives	23,270	(2,665)
Tax benefit on exercise of stock options	(301)	487
Change in bank-owned life insurance	(7,870)	(8,416)
Stock-based compensation	4,537	6,334
Depreciation and amortization	40,820	37,452
Net amortization of securities discounts and premiums	47,468	68,579
Net realized gains on financial instruments and other assets	(7,917)	(19,631)
Net gain on mortgage loans held for sale	(79,045)	(85,262)
Mortgage loans originated for resale	(3,232,520)	(2,634,809)
Proceeds from sale of mortgage loans held for resale	3,364,095	2,590,960
Capitalized mortgage servicing rights	(39,157)	(29,754)
Change in trading and fair value option securities	177,953	189,182
Change in receivables	7,716	7,328
Change in other assets	58,311	(5,747)
Change in accrued interest, taxes and expense	5,398	29,220
Change in other liabilities	(5,676)	28,980
Net cash provided by operating activities	568,964	448,645
Cash Flows From Investing Activities:
Proceeds from maturities or redemptions of investment securities	113,570	67,571
Proceeds from maturities or redemptions of available for sale securities	2,197,656	3,444,670
Purchases of investment securities	(261,629)	(60,542)
Purchases of available for sale securities	(3,708,188)	(6,412,356)
Proceeds from sales of available for sale securities	2,140,531	1,660,876
Change in amount receivable on unsettled securities transactions	118,032	42,671
Loans originated net of principal collected	(27,426)	(594,261)
Net payments on derivative asset contracts	(67,707)	(108,296)
Acquisitions, net of cash acquired	0	(28,671)
Proceeds from disposition of assets	80,678	135,760
Purchases of assets	(120,539)	(77,032)
Net cash provided by (used in) investing activities	464,978	(1,929,610)
Cash Flows From Financing Activities:
Net change in demand deposits, transaction deposits and savings accounts	(1,439,433)	739,943
Net change in time deposits	(247,972)	(359,656)
Net change in other borrowed funds	817,105	974,189
Repayment of subordinated debt	0	(53,787)
Net proceeds on derivative liability contracts	61,764	90,646
Net change in derivative margin accounts	(105,226)	(101,683)
Change in amount due on unsettled security transactions	(183,194)	(96,373)
Issuance of common and treasury stock, net	14,945	11,526
Tax benefit on exercise of stock options	301	(487)
Repurchase of common stock	0	(20,558)
Dividends paid	(77,486)	(73,666)
Net cash provided by (used in) financing activities	(1,159,196)	1,110,094
Net decrease in cash and cash equivalents	(125,254)	(370,871)
Cash and cash equivalents at beginning of period	1,286,239	986,365
Cash and cash equivalents at end of period	1,160,985	615,494
Cash paid for interest	51,689	66,819
Cash paid for taxes	104,589	113,663
Net loans and bank premises transferred to repossessed real estate and other assets	73,075	97,142
Residential mortgage loans guaranteed by U.S. government agencies that became eligible for repurchase during the period	88,618	84,520
Conveyance of other real estate owned guaranteed by U.S. government agencies	$ 31,641	$ 65,344