Loans and Allowances for Credit Losses Part 3 (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	$ 10,350,320	$ 9,362,898
Non-Graded, Recorded Investment	1,961,136	1,906,845
Total	12,311,456	11,269,743
Related Allowance [Abstract]
Internally Risk Graded, Allowance	127,322	160,086
Non-Graded, Allowance	43,998	47,045
Allowance For Financing Receivable Total	215,507	253,481	292,971	292,095
Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	10,111,255	9,025,862
Non-Graded, Recorded Investment	1,924,879	1,882,048
Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	140,912	160,547
Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	98,153	176,489
Non-Graded, Recorded Investment	36,257	24,797
Commercial [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	7,624,442	6,536,602
Non-Graded, Recorded Investment	17,470	18,468
Total	7,641,912	6,555,070
Related Allowance [Abstract]
Internally Risk Graded, Allowance	64,181	82,263
Non-Graded, Allowance	1,099	1,180
Allowance For Financing Receivable Total	65,280	83,443
Commercial [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	7,533,757	6,394,362
Non-Graded, Recorded Investment	17,406	18,416
Commercial [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	66,282	73,481
Commercial [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	24,403	68,759
Non-Graded, Recorded Investment	64	52
Commercial [Member] | Energy [Member]
Recorded Investment [Abstract]
Total	2,460,659	2,005,041
Commercial [Member] | Energy [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	2,448,954	2,003,288
Non-Graded, Recorded Investment	0	0
Commercial [Member] | Energy [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	9,245	1,417
Commercial [Member] | Energy [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	2,460	336
Non-Graded, Recorded Investment	0	0
Commercial [Member] | Services [Member]
Recorded Investment [Abstract]
Total	2,164,186	1,761,538
Commercial [Member] | Services [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	2,119,734	1,713,232
Non-Graded, Recorded Investment	0	0
Commercial [Member] | Services [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	32,362	31,338
Commercial [Member] | Services [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	12,090	16,968
Non-Graded, Recorded Investment	0	0
Commercial [Member] | Wholesale and retail [Member]
Recorded Investment [Abstract]
Total	1,106,439	967,426
Commercial [Member] | Wholesale and retail [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,093,413	912,090
Non-Graded, Recorded Investment	0	0
Commercial [Member] | Wholesale and retail [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	9,949	34,156
Commercial [Member] | Wholesale and retail [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	3,077	21,180
Non-Graded, Recorded Investment	0	0
Commercial [Member] | Manufacturing [Member]
Recorded Investment [Abstract]
Total	348,484	336,733
Commercial [Member] | Manufacturing [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	337,132	311,292
Non-Graded, Recorded Investment	0	0
Commercial [Member] | Manufacturing [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	9,345	2,390
Commercial [Member] | Manufacturing [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	2,007	23,051
Non-Graded, Recorded Investment	0	0
Commercial [Member] | Integrated food services [Member]
Recorded Investment [Abstract]
Total	191,106	204,311
Commercial [Member] | Integrated food services [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	190,422	203,555
Non-Graded, Recorded Investment	0	0
Commercial [Member] | Integrated food services [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0	756
Commercial [Member] | Integrated food services [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	684	0
Non-Graded, Recorded Investment	0	0
Commercial [Member] | Healthcare [Member]
Recorded Investment [Abstract]
Total	1,081,406	978,160
Commercial [Member] | Healthcare [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,077,773	969,260
Non-Graded, Recorded Investment	0	0
Commercial [Member] | Healthcare [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	467	3,414
Commercial [Member] | Healthcare [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	3,166	5,486
Non-Graded, Recorded Investment	0	0
Commercial [Member] | Other commercial and industrial [Member]
Recorded Investment [Abstract]
Total	289,632	301,861
Commercial [Member] | Other commercial and industrial [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	266,329	281,645
Non-Graded, Recorded Investment	17,406	18,416
Commercial [Member] | Other commercial and industrial [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	4,914	10
Commercial [Member] | Other commercial and industrial [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	919	1,738
Non-Graded, Recorded Investment	64	52
Commercial Real Estate [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	2,228,999	2,291,303
Non-Graded, Recorded Investment	0	0
Total	2,228,999	2,291,303
Related Allowance [Abstract]
Internally Risk Graded, Allowance	54,884	67,034
Non-Graded, Allowance	0	0
Allowance For Financing Receivable Total	54,884	67,034
Commercial Real Estate [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	2,105,105	2,124,872
Non-Graded, Recorded Investment	0	0
Commercial Real Estate [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	63,268	67,238
Commercial Real Estate [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	60,626	99,193
Non-Graded, Recorded Investment	0	0
Commercial Real Estate [Member] | Construction and land development [Member]
Recorded Investment [Abstract]
Total	253,093	342,054
Commercial Real Estate [Member] | Construction and land development [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	204,010	252,936
Non-Graded, Recorded Investment	0	0
Commercial Real Estate [Member] | Construction and land development [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	22,952	27,244
Commercial Real Estate [Member] | Construction and land development [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	26,131	61,874
Non-Graded, Recorded Investment	0	0
Commercial Real Estate [Member] | Retail [Member]
Recorded Investment [Abstract]
Total	522,786	509,402
Commercial Real Estate [Member] | Retail [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	508,342	499,295
Non-Graded, Recorded Investment	0	0
Commercial Real Estate [Member] | Retail [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	6,327	3,244
Commercial Real Estate [Member] | Retail [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	8,117	6,863
Non-Graded, Recorded Investment	0	0
Commercial Real Estate [Member] | Office [Member]
Recorded Investment [Abstract]
Total	427,872	405,923
Commercial Real Estate [Member] | Office [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	405,763	381,918
Non-Graded, Recorded Investment	0	0
Commercial Real Estate [Member] | Office [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	15,280	12,548
Commercial Real Estate [Member] | Office [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	6,829	11,457
Non-Graded, Recorded Investment	0	0
Commercial Real Estate [Member] | Multifamily [Member]
Recorded Investment [Abstract]
Total	402,896	369,028
Commercial Real Estate [Member] | Multifamily [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	393,566	357,436
Non-Graded, Recorded Investment	0	0
Commercial Real Estate [Member] | Multifamily [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	6,624	8,079
Commercial Real Estate [Member] | Multifamily [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	2,706	3,513
Non-Graded, Recorded Investment	0	0
Commercial Real Estate [Member] | Industrial [Member]
Recorded Investment [Abstract]
Total	245,994	278,186
Commercial Real Estate [Member] | Industrial [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	241,761	277,906
Non-Graded, Recorded Investment	0	0
Commercial Real Estate [Member] | Industrial [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	265	280
Commercial Real Estate [Member] | Industrial [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	3,968	0
Non-Graded, Recorded Investment	0	0
Commercial Real Estate [Member] | Other commercial real estate [Member]
Recorded Investment [Abstract]
Total	376,358	386,710
Commercial Real Estate [Member] | Other commercial real estate [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	351,663	355,381
Non-Graded, Recorded Investment	0	0
Commercial Real Estate [Member] | Other commercial real estate [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	11,820	15,843
Commercial Real Estate [Member] | Other commercial real estate [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	12,875	15,486
Non-Graded, Recorded Investment	0	0
Residential Mortgage [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	265,503	317,798
Non-Graded, Recorded Investment	1,779,537	1,656,729
Total	2,045,040	1,974,527
Related Allowance [Abstract]
Internally Risk Graded, Allowance	5,270	8,262
Non-Graded, Allowance	36,433	38,214
Allowance For Financing Receivable Total	41,703	46,476
Residential Mortgage [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	242,823	294,478
Non-Graded, Recorded Investment	1,745,338	1,634,403
Residential Mortgage [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	10,271	15,879
Residential Mortgage [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	12,409	7,441
Non-Graded, Recorded Investment	34,199	22,326
Residential Mortgage [Member] | Permanent mortgage [Member]
Recorded Investment [Abstract]
Total	1,123,965	1,157,133
Residential Mortgage [Member] | Permanent mortgage [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	242,823	294,478
Non-Graded, Recorded Investment	831,008	821,410
Residential Mortgage [Member] | Permanent mortgage [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	10,271	15,879
Residential Mortgage [Member] | Permanent mortgage [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	12,409	7,441
Non-Graded, Recorded Investment	27,454	17,925
Residential Mortgage [Member] | Permanent mortgages guaranteed by U.S. government agencies [Member]
Recorded Investment [Abstract]
Total	160,444	184,973
Residential Mortgage [Member] | Permanent mortgages guaranteed by U.S. government agencies [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0	0
Non-Graded, Recorded Investment	159,955	184,973
Residential Mortgage [Member] | Permanent mortgages guaranteed by U.S. government agencies [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0	0
Residential Mortgage [Member] | Permanent mortgages guaranteed by U.S. government agencies [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0	0
Non-Graded, Recorded Investment	489	0
Residential Mortgage [Member] | Home equity [Member]
Recorded Investment [Abstract]
Total	760,631	632,421
Residential Mortgage [Member] | Home equity [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0	0
Non-Graded, Recorded Investment	754,375	628,020
Residential Mortgage [Member] | Home equity [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0	0
Residential Mortgage [Member] | Home equity [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0	0
Non-Graded, Recorded Investment	6,256	4,401
Consumer [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	231,376	217,195
Non-Graded, Recorded Investment	164,129	231,648
Total	395,505	448,843
Related Allowance [Abstract]
Internally Risk Graded, Allowance	2,987	2,527
Non-Graded, Allowance	6,466	7,651
Allowance For Financing Receivable Total	9,453	10,178
Consumer [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	229,570	212,150
Non-Graded, Recorded Investment	162,135	229,229
Consumer [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,091	3,949
Consumer [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	715	1,096
Non-Graded, Recorded Investment	1,994	2,419
Consumer [Member] | Indirect automobile [Member]
Recorded Investment [Abstract]
Total	34,735	105,149
Consumer [Member] | Indirect automobile [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0	0
Non-Graded, Recorded Investment	33,157	102,955
Consumer [Member] | Indirect automobile [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0	0
Consumer [Member] | Indirect automobile [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0	0
Non-Graded, Recorded Investment	1,578	2,194
Consumer [Member] | Other consumer [Member]
Recorded Investment [Abstract]
Total	360,770	343,694
Consumer [Member] | Other consumer [Member] | Performing [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	229,570	212,150
Non-Graded, Recorded Investment	128,978	126,274
Consumer [Member] | Other consumer [Member] | Potential Problem [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	1,091	3,949
Consumer [Member] | Other consumer [Member] | Nonaccrual [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	715	1,096
Non-Graded, Recorded Investment	416	225
Allocated Class of Receivables [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	10,350,320	9,362,898
Non-Graded, Recorded Investment	1,961,136	1,906,845
Total	12,311,456	11,269,743
Related Allowance [Abstract]
Internally Risk Graded, Allowance	127,322	160,086
Non-Graded, Allowance	43,998	47,045
Allowance For Financing Receivable Total	171,320	207,131
Unallocated Financing Receivables [Member]
Recorded Investment [Abstract]
Internally Risk Graded, Recorded Investment	0	0
Non-Graded, Recorded Investment	0	0
Total	0	0
Related Allowance [Abstract]
Internally Risk Graded, Allowance	0	0
Non-Graded, Allowance	0	0
Allowance For Financing Receivable Total	$ 44,187	$ 46,350	$ 26,736	$ 18,252