Loans And Allowance For Credit Losses (Summary Of Past Due Loans (Accruing And Nonaccruing)) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012		Dec. 31, 2011
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	$ 36,141,316		$ 36,331,483
30-89 days past due	221,354		295,136
90+ days past due	510,680		518,033
Total past due	732,034		813,169
Total loans	36,873,350		37,144,652
Accruing loans 90+ days past due	99,913		93,726
Nonaccrual loans that are current	319,359	[1]	380,883	[1]
Loans Held For Sale [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	139,215		183,344
30-89 days past due	30		0
90+ days past due	0		18,246
Total past due	30		18,246
Total loans	139,245		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	541,689		634,113
30-89 days past due	17,430		27,791
90+ days past due	83,127		88,966
Total past due	100,557		116,757
Total loans	642,246		750,870
Accruing loans 90+ days past due	70,453		74,611
Nonaccrual loans that are current	7,395	[1]	6,812	[1]
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	18,755,690		18,970,869
30-89 days past due	108,124		157,550
90+ days past due	212,668		185,945
Total past due	320,792		343,495
Total loans	19,076,482		19,314,364
Accruing loans 90+ days past due	12,148		8,196
Nonaccrual loans that are current	141,675	[1]	134,753	[1]
Commercial [Member] | Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	10,242,577		10,198,434
30-89 days past due	53,792		62,153
90+ days past due	86,307		74,271
Total past due	140,099		136,424
Total loans	10,382,676		10,334,858
Accruing loans 90+ days past due	7,440		4,966
Nonaccrual loans that are current	44,566	[1]	47,939	[1]
Commercial [Member] | Leasing [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	404,387		377,914
30-89 days past due	825		1,634
90+ days past due	1,290		161
Total past due	2,115		1,795
Total loans	406,502		379,709
Accruing loans 90+ days past due	34		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	7,632,058		7,953,280
30-89 days past due	53,507		93,763
90+ days past due	125,071		111,513
Total past due	178,578		205,276
Total loans	7,810,636		8,158,556
Accruing loans 90+ days past due	4,674		3,230
Nonaccrual loans that are current	97,109	[1]	85,495	[1]
Commercial [Member] | Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	476,668		441,241
30-89 days past due	0		0
90+ days past due	0		0
Total past due	0		0
Total loans	476,668		441,241
Accruing loans 90+ days past due	0		0
Nonaccrual loans that are current	0	[1]	0	[1]
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	9,893,933		9,907,812
30-89 days past due	69,323		73,154
90+ days past due	147,089		167,377
Total past due	216,412		240,531
Total loans	10,110,345		10,148,343
Accruing loans 90+ days past due	3,556		6,641
Nonaccrual loans that are current	131,744	[1]	196,442	[1]
Commercial Real Estate [Member] | Construction And Land Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	2,008,441		2,137,544
30-89 days past due	32,853		21,562
90+ days past due	57,770		105,803
Total past due	90,623		127,365
Total loans	2,099,064		2,264,909
Accruing loans 90+ days past due	2,335		2,471
Nonaccrual loans that are current	50,991	[1]	107,991	[1]
Commercial Real Estate [Member] | Term [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	7,885,492		7,770,268
30-89 days past due	36,470		51,592
90+ days past due	89,319		61,574
Total past due	125,789		113,166
Total loans	8,011,281		7,883,434
Accruing loans 90+ days past due	1,221		4,170
Nonaccrual loans that are current	80,753	[1]	88,451	[1]
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	6,950,004		6,818,689
30-89 days past due	26,477		36,641
90+ days past due	67,796		75,745
Total past due	94,273		112,386
Total loans	7,044,277		6,931,075
Accruing loans 90+ days past due	13,756		4,278
Nonaccrual loans that are current	38,545	[1]	42,876	[1]
Consumer [Member] | Home Equity Credit Line [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	2,169,606		2,169,190
30-89 days past due	6,188		8,669
90+ days past due	5,063		9,569
Total past due	11,251		18,238
Total loans	2,180,857		2,187,428
Accruing loans 90+ days past due	0		0
Nonaccrual loans that are current	6,001	[1]	5,542	[1]
Consumer [Member] | 1-4 Family Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	3,960,786		3,846,012
30-89 days past due	13,405		18,985
90+ days past due	44,667		56,219
Total past due	58,072		75,204
Total loans	4,018,858		3,921,216
Accruing loans 90+ days past due	459		2,833
Nonaccrual loans that are current	27,160	[1]	32,067	[1]
Consumer [Member] | Construction And Other Consumer Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	310,855		294,371
30-89 days past due	2,101		5,008
90+ days past due	14,911		6,494
Total past due	17,012		11,502
Total loans	327,867		305,873
Accruing loans 90+ days past due	12,096		136
Nonaccrual loans that are current	4,339	[1]	4,773	[1]
Consumer [Member] | Bankcard And Other Revolving Plans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	279,221		287,541
30-89 days past due	3,144		1,984
90+ days past due	1,747		1,493
Total past due	4,891		3,477
Total loans	284,112		291,018
Accruing loans 90+ days past due	1,197		1,309
Nonaccrual loans that are current	580	[1]	122	[1]
Consumer [Member] | Other [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current	229,536		221,575
30-89 days past due	1,639		1,995
90+ days past due	1,408		1,970
Total past due	3,047		3,965
Total loans	232,583		225,540
Accruing loans 90+ days past due	4		0
Nonaccrual loans that are current	$ 465	[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.