Loans And Allowance For Credit Losses (Summary Of Past Due Loans (Accruing And Nonaccruing)) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	$ 36,536,556		$ 36,331,483
30-89 days past due	212,484		295,136
90+ days past due	421,779		518,033
Total past due	634,263		813,169
Total loans	37,170,819		37,144,652
Accruing loans 90+ days past due	75,421		93,726
Nonaccrual loans that are current	319,536	[1]	380,883	[1]
Loans Held For Sale [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	220,211		183,344
30-89 days past due	29		0
90+ days past due	0		18,246
Total past due	29		18,246
Total loans	220,240		201,590
Accruing loans 90+ days past due	0		30
Nonaccrual loans that are current	0	[1]	0	[1]
FDIC-Supported Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	501,245		634,113
30-89 days past due	15,983		27,791
90+ days past due	71,338		88,966
Total past due	87,321		116,757
Total loans	588,566		750,870
Accruing loans 90+ days past due	60,913		74,611
Nonaccrual loans that are current	8,508	[1]	6,812	[1]
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	19,030,923		18,970,869
30-89 days past due	103,946		157,550
90+ days past due	156,864		185,945
Total past due	260,810		343,495
Total loans	19,291,733		19,314,364
Accruing loans 90+ days past due	7,656		8,196
Nonaccrual loans that are current	156,308	[1]	134,753	[1]
Commercial [Member] | Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	10,635,534		10,198,434
30-89 days past due	47,041		62,153
90+ days past due	65,691		74,271
Total past due	112,732		136,424
Total loans	10,748,266		10,334,858
Accruing loans 90+ days past due	6,286		4,966
Nonaccrual loans that are current	37,630	[1]	47,939	[1]
Commercial [Member] | Leasing [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	402,741		377,914
30-89 days past due	878		1,634
90+ days past due	1,393		161
Total past due	2,271		1,795
Total loans	405,012		379,709
Accruing loans 90+ days past due	0		0
Nonaccrual loans that are current	0	[1]	1,319	[1]
Commercial [Member] | Owner Occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	7,523,411		7,953,280
30-89 days past due	56,027		93,763
90+ days past due	89,780		111,513
Total past due	145,807		205,276
Total loans	7,669,218		8,158,556
Accruing loans 90+ days past due	1,370		3,230
Nonaccrual loans that are current	112,781	[1]	85,495	[1]
Commercial [Member] | Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	469,237		441,241
30-89 days past due	0		0
90+ days past due	0		0
Total past due	0		0
Total loans	469,237		441,241
Accruing loans 90+ days past due	0		0
Nonaccrual loans that are current	5,897	[1]	0	[1]
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	9,892,105		9,907,812
30-89 days past due	59,375		73,154
90+ days past due	144,252		167,377
Total past due	203,627		240,531
Total loans	10,095,732		10,148,343
Accruing loans 90+ days past due	5,164		6,641
Nonaccrual loans that are current	124,517	[1]	196,442	[1]
Commercial Real Estate [Member] | Construction And Land Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	1,874,942		2,137,544
30-89 days past due	16,242		21,562
90+ days past due	65,002		105,803
Total past due	81,244		127,365
Total loans	1,956,186		2,264,909
Accruing loans 90+ days past due	1,378		2,471
Nonaccrual loans that are current	61,089	[1]	107,991	[1]
Commercial Real Estate [Member] | Term [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	8,017,163		7,770,268
30-89 days past due	43,133		51,592
90+ days past due	79,250		61,574
Total past due	122,383		113,166
Total loans	8,139,546		7,883,434
Accruing loans 90+ days past due	3,786		4,170
Nonaccrual loans that are current	63,428	[1]	88,451	[1]
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	7,112,283		6,818,689
30-89 days past due	33,180		36,641
90+ days past due	49,325		75,745
Total past due	82,505		112,386
Total loans	7,194,788		6,931,075
Accruing loans 90+ days past due	1,688		4,278
Nonaccrual loans that are current	30,203	[1]	42,876	[1]
Consumer [Member] | Home Equity Credit Line [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	2,165,086		2,169,190
30-89 days past due	6,430		8,669
90+ days past due	3,822		9,569
Total past due	10,252		18,238
Total loans	2,175,338		2,187,428
Accruing loans 90+ days past due	0		0
Nonaccrual loans that are current	5,558	[1]	5,542	[1]
Consumer [Member] | 1-4 Family Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	4,121,285		3,846,012
30-89 days past due	19,792		18,985
90+ days past due	39,925		56,219
Total past due	59,717		75,204
Total loans	4,181,002		3,921,216
Accruing loans 90+ days past due	362		2,833
Nonaccrual loans that are current	21,451	[1]	32,067	[1]
Consumer [Member] | Construction And Other Consumer Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	314,251		294,371
30-89 days past due	2,615		5,008
90+ days past due	3,221		6,494
Total past due	5,836		11,502
Total loans	320,087		305,873
Accruing loans 90+ days past due	292		136
Nonaccrual loans that are current	2,789	[1]	4,773	[1]
Consumer [Member] | Bankcard And Other Revolving Plans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	290,295		287,541
30-89 days past due	3,360		1,984
90+ days past due	1,172		1,493
Total past due	4,532		3,477
Total loans	294,827		291,018
Accruing loans 90+ days past due	1,027		1,309
Nonaccrual loans that are current	227	[1]	122	[1]
Consumer [Member] | Other [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	221,366		221,575
30-89 days past due	983		1,995
90+ days past due	1,185		1,970
Total past due	2,168		3,965
Total loans	223,534		225,540
Accruing loans 90+ days past due	7		0
Nonaccrual loans that are current	$ 178	[1]	$ 372	[1]

[1] Represents nonaccrual loans that are not past due more than 30 days; however, full payment of principal and interest is still not expected.