Loans And Allowance For Credit Losses (Summary Of Outstanding Loan Balances (Accruing And Nonaccruing) Categorized By Credit Quality Indicators) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans held for sale	$ 139,245	$ 201,590
Commercial and industrial	10,382,676	10,334,858
Leasing	406,502	379,709
Owner occupied	7,810,636	8,158,556
Municipal	476,668	441,241
Total commercial	19,076,482	19,314,364
Construction and land development	2,099,064	2,264,909
Term	8,011,281	7,883,434
Total commercial real estate	10,110,345	10,148,343
Home equity credit line	2,180,857	2,187,428
1-4 family residential	4,018,858	3,921,216
Construction and other consumer real estate	327,867	305,873
Bankcard and other revolving plans	284,112	291,018
Other	232,583	225,540
Total consumer	7,044,277	6,931,075
FDIC-supported loans	642,246	750,870
Total loans	36,873,350	37,144,652
Pass [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans held for sale	138,633	182,626
Total loans	33,937,195	33,972,984
Special Mention [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans held for sale	0	0
Total loans	851,198	919,598
Sub-Standard [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans held for sale	612	18,964
Total loans	2,054,966	2,225,424
Doubtful [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans held for sale	0	0
Total loans	29,991	26,646
Total Allowance [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans held for sale	0	0
Total loans	971,716	1,049,958
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Commercial and industrial	10,382,676	10,334,858
Leasing	406,502	379,709
Owner occupied	7,810,636	8,158,556
Municipal	476,668	441,241
Total commercial	19,076,482	19,314,364
Total loans	19,076,482	19,314,364
Commercial [Member] | Pass [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Commercial and industrial	9,750,389	9,612,143
Leasing	395,595	362,711
Owner occupied	7,104,691	7,481,207
Municipal	465,266	425,807
Total commercial	17,715,941	17,881,868
Commercial [Member] | Special Mention [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Commercial and industrial	275,392	271,845
Leasing	3,232	5,878
Owner occupied	154,787	184,821
Municipal	11,402	15,434
Total commercial	444,813	477,978
Commercial [Member] | Sub-Standard [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Commercial and industrial	343,102	442,139
Leasing	7,675	11,120
Owner occupied	544,520	486,584
Municipal	0	0
Total commercial	895,297	939,843
Commercial [Member] | Doubtful [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Commercial and industrial	13,793	8,731
Leasing	0	0
Owner occupied	6,638	5,944
Municipal	0	0
Total commercial	20,431	14,675
Commercial [Member] | Total Allowance [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total commercial	616,359	627,825
Construction And Land Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Construction and land development	2,099,064	2,264,909
Construction And Land Development [Member] | Pass [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Construction and land development	1,655,632	1,647,741
Construction And Land Development [Member] | Special Mention [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Construction and land development	162,031	187,323
Construction And Land Development [Member] | Sub-Standard [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Construction and land development	280,118	426,152
Construction And Land Development [Member] | Doubtful [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Construction and land development	1,283	3,693
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Term	8,011,281	7,883,434
Total commercial real estate	10,110,345	10,148,343
Total loans	10,110,345	10,148,343
Commercial Real Estate [Member] | Pass [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Term	7,328,172	7,243,678
Total commercial real estate	8,983,804	8,891,419
Commercial Real Estate [Member] | Special Mention [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Term	200,661	196,377
Total commercial real estate	362,692	383,700
Commercial Real Estate [Member] | Sub-Standard [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Term	475,965	437,390
Total commercial real estate	756,083	863,542
Commercial Real Estate [Member] | Doubtful [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Term	6,483	5,989
Total commercial real estate	7,766	9,682
Commercial Real Estate [Member] | Total Allowance [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total commercial real estate	232,049	275,546
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Home equity credit line	2,180,857	2,187,428
1-4 family residential	4,018,858	3,921,216
Construction and other consumer real estate	327,867	305,873
Bankcard and other revolving plans	284,112	291,018
Other	232,583	225,540
Total consumer	7,044,277	6,931,075
Total loans	7,044,277	6,931,075
Consumer [Member] | Pass [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Home equity credit line	2,134,373	2,136,190
1-4 family residential	3,889,904	3,788,958
Construction and other consumer real estate	303,565	274,712
Bankcard and other revolving plans	272,140	278,767
Other	227,976	221,114
Total consumer	6,827,958	6,699,741
Consumer [Member] | Special Mention [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Home equity credit line	103	106
1-4 family residential	2,613	5,736
Construction and other consumer real estate	12,127	12,206
Bankcard and other revolving plans	3,553	3,832
Other	0	163
Total consumer	18,396	22,043
Consumer [Member] | Sub-Standard [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Home equity credit line	46,333	51,089
1-4 family residential	126,126	126,277
Construction and other consumer real estate	10,644	16,967
Bankcard and other revolving plans	8,419	8,419
Other	4,607	4,256
Total consumer	196,129	207,008
Consumer [Member] | Doubtful [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Home equity credit line	48	43
1-4 family residential	215	245
Construction and other consumer real estate	1,531	1,988
Bankcard and other revolving plans	0	0
Other	0	7
Total consumer	1,794	2,283
Consumer [Member] | Total Allowance [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total consumer	102,391	123,115
FDIC-Supported Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
FDIC-supported loans	642,246	750,870
FDIC-Supported Loans [Member] | Pass [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
FDIC-supported loans	409,492	499,956
FDIC-Supported Loans [Member] | Special Mention [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
FDIC-supported loans	25,297	35,877
FDIC-Supported Loans [Member] | Sub-Standard [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
FDIC-supported loans	207,457	215,031
FDIC-Supported Loans [Member] | Doubtful [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
FDIC-supported loans	0	6
FDIC-Supported Loans [Member] | Total Allowance [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
FDIC-supported loans	$ 20,917	$ 23,472