Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Cash Flows From Operating Activities:
Net income	$ 77,043	$ 89,059
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	0	(8,000)
Change in fair value of mortgage servicing rights	4,461	(2,658)
Unrealized losses from derivative contracts	563	9,334
Tax effect from equity compensation, net	(1,732)	337
Change in bank-owned life insurance	(2,106)	(3,226)
Stock-based compensation	2,863	(751)
Depreciation and amortization	12,362	13,392
Net amortization of securities discounts and premiums	14,560	16,507
Net realized gains on financial instruments and other assets	(1,202)	(5,436)
Net gain on mortgage loans held for sale	(11,968)	(30,235)
Mortgage loans originated for sale	(727,516)	(956,315)
Proceeds from sale of mortgage loans held for resale	713,002	993,776
Capitalized mortgage servicing rights	(8,644)	(11,433)
Change in trading and fair value option securities	10,890	81,022
Change in receivables	3,246	(2,554)
Change in other assets	14,111	7,376
Change in accrued interest, taxes and expense	(41,114)	15,680
Change in other liabilities	1,555	33,543
Net cash provided by operating activities	60,374	239,418
Cash Flows From Investing Activities:
Proceeds from maturities or redemptions of investment securities	13,019	20,485
Proceeds from maturities or redemptions of available for sale securities	403,191	991,514
Purchases of investment securities	(5,834)	(110,957)
Purchases of available for sale securities	(679,171)	(1,529,068)
Proceeds from sales of available for sale securities	531,385	728,424
Change in amount receivable on unsettled securities transactions	(1,025)	20,364
Loans originated net of principal collected	(271,214)	221,433
Net payments on derivative asset contracts	40,220	17,454
Acquisitions, net of cash acquired	(12,624)	0
Proceeds from disposition of assets	20,071	26,870
Purchases of assets	(20,945)	(73,612)
Net cash provided by investing activities	17,073	312,907
Cash Flows From Financing Activities:
Net change in demand deposits, transaction deposits and savings accounts	154,205	(1,250,831)
Net change in time deposits	(33,819)	(67,938)
Net change in other borrowed funds	221,650	659,003
Net proceeds on derivative liability contracts	(40,228)	(20,893)
Net change in derivative margin accounts	(84,368)	(57,241)
Change in amount due on unsettled security transactions	(6,099)	(138,469)
Issuance of common and treasury stock, net	3,655	9,542
Tax effect from equity compensation, net	1,732	(337)
Dividends paid	(27,382)	(25,783)
Net cash provided by (used in) financing activities	189,346	(892,947)
Net increase (decrease) in cash and cash equivalents	266,793	(340,622)
Cash and cash equivalents at beginning of period	1,087,213	1,286,239
Cash and cash equivalents at end of period	1,354,006	945,617
Cash paid for interest	14,394	16,390
Cash paid for taxes	56	5,953
Net loans and bank premises transferred to repossessed real estate and other assets	19,577	22,299
Residential mortgage loans guaranteed by U.S. government agencies that became eligible for repurchase during the period	31,441	28,192
Conveyance of other real estate owned guaranteed by U.S. government agencies	$ 9,100	$ 11,155