Loans And Allowance For Credit Losses (Summary Of Past Due Loans (Accruing And Nonaccruing)) (Details) - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans Receivable Held-for-sale, Net		$ 171,934	$ 149,880
Current		42,339,877	40,363,353
30-89 days past due		150,340	147,980
90+ days past due		159,048	138,209
Total past due		309,388	286,189
Loans and Leases Receivable, Gross		42,649,265	40,649,542
Accruing loans 90+ days past due		35,848	32,024
Nonaccrual loans that are current	[1]	380,781	217,427
Financing Receivable, Recorded Investment, Nonaccrual Status		528,329	349,860
loans held for sale [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status		40,330	0
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status		442,738	242,567
Commercial Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		21,401,174	21,308,301
30-89 days past due		112,101	106,068
90+ days past due		101,722	64,645
Total past due		213,823	170,713
Loans and Leases Receivable, Gross		21,614,997	21,479,014
Accruing loans 90+ days past due		17,772	6,737
Nonaccrual loans that are current		344,803	166,186
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		2,009,344	1,835,360
30-89 days past due		7,208	842
90+ days past due		2,103	5,300
Total past due		9,311	6,142
Loans and Leases Receivable, Gross		2,018,655	1,841,502
Accruing loans 90+ days past due		368	0
Nonaccrual loans that are current	[1]	310	1,745
Financing Receivable, Recorded Investment, Nonaccrual Status		36,121	47,298
Home Equity Credit Line [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		2,635,321	2,407,972
30-89 days past due		3,868	4,717
90+ days past due		6,003	3,668
Total past due		9,871	8,385
Loans and Leases Receivable, Gross		2,645,192	2,416,357
Accruing loans 90+ days past due		1,500	0
Nonaccrual loans that are current	[1]	4,474	3,053
Financing Receivable, Recorded Investment, Nonaccrual Status		10,842	8,270
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		189,044	186,436
30-89 days past due		711	647
90+ days past due		39	66
Total past due		750	713
Loans and Leases Receivable, Gross		189,794	187,149
Accruing loans 90+ days past due		0	0
Nonaccrual loans that are current	[1]	70	83
Financing Receivable, Recorded Investment, Nonaccrual Status		139	186
Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		13,306,132	13,114,045
30-89 days past due		71,446	60,523
90+ days past due		74,308	36,913
Total past due		145,754	97,436
Loans and Leases Receivable, Gross		13,451,886	13,211,481
Accruing loans 90+ days past due		10,321	3,065
Nonaccrual loans that are current	[1]	286,883	117,942
Financing Receivable, Recorded Investment, Nonaccrual Status		354,172	163,906
Leasing [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		422,969	440,963
30-89 days past due		0	183
90+ days past due		0	520
Total past due		0	703
Loans and Leases Receivable, Gross		422,969	441,666
Accruing loans 90+ days past due		0	0
Nonaccrual loans that are current	[1]	13,920	3,309
Financing Receivable, Recorded Investment, Nonaccrual Status		13,920	3,829
Owner Occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		6,893,739	7,085,086
30-89 days past due		40,655	37,776
90+ days past due		27,413	27,166
Total past due		68,068	64,942
Loans and Leases Receivable, Gross		6,961,807	7,150,028
Accruing loans 90+ days past due		7,450	3,626
Nonaccrual loans that are current	[1]	43,148	43,984
Financing Receivable, Recorded Investment, Nonaccrual Status		73,794	73,881
Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		778,334	668,207
30-89 days past due		0	7,586
90+ days past due		1	46
Total past due		1	7,632
Loans and Leases Receivable, Gross		778,335	675,839
Accruing loans 90+ days past due		1	46
Nonaccrual loans that are current	[1]	852	951
Financing Receivable, Recorded Investment, Nonaccrual Status		852	951
Term [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		9,290,756	8,469,390
30-89 days past due		8,806	10,424
90+ days past due		22,576	34,587
Total past due		31,382	45,011
Loans and Leases Receivable, Gross		9,322,138	8,514,401
Accruing loans 90+ days past due		12,349	21,697
Nonaccrual loans that are current	[1]	18,469	24,867
Financing Receivable, Recorded Investment, Nonaccrual Status		29,012	40,253
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		11,300,100	10,304,750
30-89 days past due		16,014	11,266
90+ days past due		24,679	39,887
Total past due		40,693	51,153
Loans and Leases Receivable, Gross		11,340,793	10,355,903
Accruing loans 90+ days past due		12,717	21,697
Nonaccrual loans that are current		18,779	26,612
1-4 Family Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		5,857,429	5,340,549
30-89 days past due		11,982	14,828
90+ days past due		21,303	26,722
Total past due		33,285	41,550
Loans and Leases Receivable, Gross		5,890,714	5,382,099
Accruing loans 90+ days past due		121	1,036
Nonaccrual loans that are current	[1]	11,342	20,939
Financing Receivable, Recorded Investment, Nonaccrual Status		35,577	50,254
Construction And Other Consumer Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		479,383	374,987
30-89 days past due		3,258	8,593
90+ days past due		4,071	1,660
Total past due		7,329	10,253
Loans and Leases Receivable, Gross		486,712	385,240
Accruing loans 90+ days past due		2,557	1,337
Nonaccrual loans that are current	[1]	162	408
Financing Receivable, Recorded Investment, Nonaccrual Status		1,677	748
Bankcard And Other Revolving Plans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		477,426	440,358
30-89 days past due		2,406	1,861
90+ days past due		1,231	1,561
Total past due		3,637	3,422
Loans and Leases Receivable, Gross		481,063	443,780
Accruing loans 90+ days past due		1,181	1,217
Nonaccrual loans that are current	[1]	1,151	146
Financing Receivable, Recorded Investment, Nonaccrual Status		1,235	537
Consumer Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		9,638,603	8,750,302
30-89 days past due		22,225	30,646
90+ days past due		32,647	33,677
Total past due		54,872	64,323
Loans and Leases Receivable, Gross		9,693,475	8,814,625
Accruing loans 90+ days past due		5,359	3,590
Nonaccrual loans that are current		17,199	24,629
Financing Receivable, Recorded Investment, Nonaccrual Status		49,470	59,995
Special Mention [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans and Leases Receivable, Gross		508,045	634,390
loans held for sale [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current		171,934	149,880
30-89 days past due		0	0
90+ days past due		0	0
Total past due		0	0
Loans and Leases Receivable, Gross		171,934	149,880
Accruing loans 90+ days past due		0	0
Financing Receivable, Recorded Investment, Nonaccrual Status		$ 40,330	$ 0

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