Fair Value Measurements (Estimated Fair Values Of Financial Instruments) (Details) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2010
Cash and cash equivalents	$ 4,487,361	$ 2,820,977	$ 2,852,884
Loans, net	7,974,144	7,990,704	7,926,791
Deposits	16,063,873	14,479,342	14,530,087
Federal funds purchased and repurchase agreements	658,246	475,673	430,737
Junior subordinated deferrable interest debentures	123,712	123,712	123,712
Subordinated notes payable and other borrowings	100,031	250,045	250,049
Carrying Amount [Member]
Cash and cash equivalents	4,487,361	2,820,977
Securities	5,721,902	5,456,200
Loans, net	7,974,259	7,990,704
Cash surrender value of life insurance policies	132,899	129,922
Non-hedging commercial loan/lease interest rate swaps, caps and floors	61,193	44,723
Commodity and foreign exchange derivatives	32,930	14,177
Accrued interest receivable	44,407	72,328
Deposits	16,063,873	14,479,342
Federal funds purchased and repurchase agreements	658,246	475,673
Junior subordinated deferrable interest debentures	123,712	123,712
Subordinated notes payable and other borrowings	100,031	250,045
Commercial loan/lease interest rate swaps designated as hedges of fair value	8,805	8,350
Interest rate swap on junior subordinated deferrable interest debentures designated as a hedge of cash flows	9,137	9,895
Non-hedging commercial loan/lease interest rate swaps, caps and floors	61,476	45,054
Commodity and foreign exchange derivatives	32,707	14,101
Accrued interest payable	3,234	9,991
Estimated Fair Value [Member]
Cash and cash equivalents	4,487,361	2,820,977
Securities	5,758,840	5,468,799
Loans, net	8,005,005	8,038,760
Cash surrender value of life insurance policies	132,899	129,922
Non-hedging commercial loan/lease interest rate swaps, caps and floors	61,193	44,723
Commodity and foreign exchange derivatives	32,930	14,177
Accrued interest receivable	44,407	72,328
Deposits	16,064,926	14,480,725
Federal funds purchased and repurchase agreements	658,246	475,673
Junior subordinated deferrable interest debentures	123,712	123,712
Subordinated notes payable and other borrowings	100,297	256,172
Commercial loan/lease interest rate swaps designated as hedges of fair value	8,805	8,350
Interest rate swap on junior subordinated deferrable interest debentures designated as a hedge of cash flows	9,137	9,895
Non-hedging commercial loan/lease interest rate swaps, caps and floors	61,476	45,054
Commodity and foreign exchange derivatives	32,707	14,101
Accrued interest payable	$ 3,234	$ 9,991