Loans and Allowances for Credit Losses Part 7 (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Financing receivable, recorded investment, aging [Abstract]
Current	$ 12,509,986,000	$ 12,014,834,000
Past due 30 to 89 days	38,099,000	37,938,000
Past due 90 days or more	143,030,000	124,274,000
Nonaccrual	101,149,000	134,410,000
Total	12,792,264,000	12,311,456,000
Commercial [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	7,922,000,000	7,611,023,000
Past due 30 to 89 days	4,112,000	5,994,000
Past due 90 days or more	349,000	428,000
Nonaccrual	16,760,000	24,467,000
Total	7,943,221,000	7,641,912,000
Energy [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	2,347,267,000	2,454,928,000
Past due 30 to 89 days	2,483,000	3,071,000
Past due 90 days or more	150,000	200,000
Nonaccrual	1,860,000	2,460,000
Total	2,351,760,000	2,460,659,000
Services [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	2,276,036,000	2,150,386,000
Past due 30 to 89 days	1,210,000	1,710,000
Past due 90 days or more	42,000	0
Nonaccrual	4,922,000	12,090,000
Total	2,282,210,000	2,164,186,000
Wholesale/retail [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	1,193,905,000	1,103,307,000
Past due 30 to 89 days	338,000	5,000
Past due 90 days or more	152,000	50,000
Nonaccrual	6,969,000	3,077,000
Total	1,201,364,000	1,106,439,000
Manufacturing [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	391,159,000	346,442,000
Past due 30 to 89 days	0	35,000
Past due 90 days or more	0	0
Nonaccrual	592,000	2,007,000
Total	391,751,000	348,484,000
Healthcare [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	1,272,660,000	1,077,022,000
Past due 30 to 89 days	0	1,040,000
Past due 90 days or more	0	178,000
Nonaccrual	1,586,000	3,166,000
Total	1,274,246,000	1,081,406,000
Integrated food services [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	150,494,000	190,416,000
Past due 30 to 89 days	0	6,000
Past due 90 days or more	0	0
Nonaccrual	0	684,000
Total	150,494,000	191,106,000
Other commercial and industrial [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	290,479,000	288,522,000
Past due 30 to 89 days	81,000	127,000
Past due 90 days or more	5,000	0
Nonaccrual	831,000	983,000
Total	291,396,000	289,632,000
Commercial Real Estate [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	2,370,684,000	2,159,287,000
Past due 30 to 89 days	2,788,000	5,657,000
Past due 90 days or more	1,031,000	3,429,000
Nonaccrual	40,850,000	60,626,000
Total	2,415,353,000	2,228,999,000
Residential construction and land development [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	188,434,000	226,962,000
Past due 30 to 89 days	428,000	0
Past due 90 days or more	19,000	0
Nonaccrual	17,377,000	26,131,000
Total	206,258,000	253,093,000
Retail [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	580,926,000	514,252,000
Past due 30 to 89 days	264,000	349,000
Past due 90 days or more	0	68,000
Nonaccrual	4,857,000	8,117,000
Total	586,047,000	522,786,000
Office [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	404,505,000	417,866,000
Past due 30 to 89 days	603,000	3,177,000
Past due 90 days or more	0	0
Nonaccrual	6,391,000	6,829,000
Total	411,499,000	427,872,000
Multifamily [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	576,495,000	400,151,000
Past due 30 to 89 days	0	39,000
Past due 90 days or more	0	0
Nonaccrual	7,000	2,706,000
Total	576,502,000	402,896,000
Industrial [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	243,625,000	242,026,000
Past due 30 to 89 days	0	0
Past due 90 days or more	0	0
Nonaccrual	252,000	3,968,000
Total	243,877,000	245,994,000
Other commercial real estate [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	376,699,000	358,030,000
Past due 30 to 89 days	1,493,000	2,092,000
Past due 90 days or more	1,012,000	3,361,000
Nonaccrual	11,966,000	12,875,000
Total	391,170,000	376,358,000
Residential Mortgage [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	1,837,885,000	1,854,347,000
Past due 30 to 89 days	30,172,000	23,687,000
Past due 90 days or more	141,649,000	120,398,000
Nonaccrual	42,320,000	46,608,000
Total	2,052,026,000	2,045,040,000
Permanent Mortgage [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	1,018,670,000	1,075,687,000
Past due 30 to 89 days	9,795,000	8,366,000
Past due 90 days or more	0	49,000
Nonaccrual	34,279,000	39,863,000
Total	1,062,744,000	1,123,965,000
Permanent mortgages guaranteed by U.S. government agencies [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	21,916,000	26,560,000
Past due 30 to 89 days	17,290,000	13,046,000
Past due 90 days or more	141,615,000	120,349,000
Nonaccrual	777,000	489,000
Total	181,598,000	160,444,000
Home equity
Financing receivable, recorded investment, aging [Abstract]
Current	797,299,000	752,100,000
Past due 30 to 89 days	3,087,000	2,275,000
Past due 90 days or more	34,000	0
Nonaccrual	7,264,000	6,256,000
Total	807,684,000	760,631,000
Consumer [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	379,417,000	390,177,000
Past due 30 to 89 days	1,027,000	2,600,000
Past due 90 days or more	1,000	19,000
Nonaccrual	1,219,000	2,709,000
Total	381,664,000	395,505,000
Indirect automobile [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	5,466,000	31,869,000
Past due 30 to 89 days	330,000	1,273,000
Past due 90 days or more	0	15,000
Nonaccrual	717,000	1,578,000
Total	6,513,000	34,735,000
Other consumer [Member]
Financing receivable, recorded investment, aging [Abstract]
Current	373,951,000	358,308,000
Past due 30 to 89 days	697,000	1,327,000
Past due 90 days or more	1,000	4,000
Nonaccrual	502,000	1,131,000
Total	$ 375,151,000	$ 360,770,000