Fair Value Measurements, Financial Instruments (Details) (USD $)													6 Months Ended		12 Months Ended	6 Months Ended		12 Months Ended	6 Months Ended		12 Months Ended	6 Months Ended		12 Months Ended	6 Months Ended		12 Months Ended	6 Months Ended		12 Months Ended	6 Months Ended		12 Months Ended
	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2009	Jun. 30, 2011 Carrying (Reported) Amount, Fair Value Disclosure [Member]	Dec. 31, 2010 Carrying (Reported) Amount, Fair Value Disclosure [Member]	Jun. 30, 2010 Carrying (Reported) Amount, Fair Value Disclosure [Member]	Jun. 30, 2011 Estimate of Fair Value, Fair Value Disclosure [Member]	Dec. 31, 2010 Estimate of Fair Value, Fair Value Disclosure [Member]	Jun. 30, 2010 Estimate of Fair Value, Fair Value Disclosure [Member]	Jun. 30, 2011 Commercial Loan [Member]	Jun. 30, 2010 Commercial Loan [Member]	Dec. 31, 2010 Commercial Loan [Member]	Jun. 30, 2011 Commercial Real Estate [Member]	Jun. 30, 2010 Commercial Real Estate [Member]	Dec. 31, 2010 Commercial Real Estate [Member]	Jun. 30, 2011 Residential Mortgage [Member]	Jun. 30, 2010 Residential Mortgage [Member]	Dec. 31, 2010 Residential Mortgage [Member]	Jun. 30, 2011 Consumer Loan [Member]	Jun. 30, 2010 Consumer Loan [Member]	Dec. 31, 2010 Consumer Loan [Member]	Jun. 30, 2011 Time Deposits [Member]	Jun. 30, 2010 Time Deposits [Member]	Dec. 31, 2010 Time Deposits [Member]	Jun. 30, 2011 Other Borrowings [Member]	Jun. 30, 2010 Other Borrowings [Member]	Dec. 31, 2010 Other Borrowings [Member]	Jun. 30, 2011 Subordinated Debentures [Member]	Jun. 30, 2010 Subordinated Debentures [Member]	Dec. 31, 2010 Subordinated Debentures [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents							$ 1,110,761,000	$ 1,269,404,000	$ 852,526,000	$ 1,110,761,000	$ 1,269,404,000	$ 852,526,000
Trading securities							99,846,000	55,467,000	62,159,000	99,846,000	55,467,000	62,159,000
Investment securities [Abstract]
Municipal and other tax-exempt							160,870,000	184,898,000	221,702,000	165,449,000	188,577,000	227,301,000
Other debt securities							188,713,000	154,655,000	131,575,000	203,798,000	157,528,000	136,585,000
Total investment securities	349,583,000		339,553,000	353,277,000			349,583,000	339,553,000	353,277,000	369,247,000	346,105,000	363,886,000
Available for sale securities [Abstract]
U.S. Treasury							1,003,000			1,003,000
Municipal and other tax-exempt							70,210,000	72,942,000	66,439,000	70,210,000	72,942,000	66,439,000
U.S. agency residential mortgage-backed securities							8,893,789,000	8,446,908,000	8,223,719,000	8,893,789,000	8,446,908,000	8,223,719,000
Private issue residential mortgage-backed securities							513,222,000	644,210,000	735,516,000	513,222,000	644,210,000	735,516,000
Other debt securities							5,893,000	6,401,000	13,064,000	5,893,000	6,401,000	13,064,000
Perpetual preferred stock							22,694,000	22,114,000	19,881,000	22,694,000	22,114,000	19,881,000
Equity securities and mutual funds							60,197,000	43,046,000	47,209,000	60,197,000	43,046,000	47,209,000
Total available for sale securities							9,567,008,000	9,235,621,000	9,105,828,000	9,567,008,000	9,235,621,000	9,105,828,000
Mortgage trading securities	553,231,000		428,021,000	534,641,000			553,231,000	428,021,000	534,641,000	553,231,000	428,021,000	534,641,000
Residential mortgage loans held for sale	169,609,000		263,413,000	227,574,000			169,609,000	263,413,000	227,574,000	169,609,000	263,413,000	227,574,000
Loans [Abstract]
Commercial							6,178,596,000	5,933,996,000	6,011,528,000	6,085,941,000	5,849,443,000	5,915,895,000
Commercial real estate							2,183,715,000	2,277,350,000	2,340,909,000	2,134,950,000	2,221,443,000	2,291,533,000
Residential mortgage							1,867,997,000	1,828,248,000	1,834,246,000	1,915,710,000	1,860,913,000	1,912,579,000
Consumer							507,236,000	603,442,000	696,034,000	507,831,000	605,656,000	704,498,000
Total	10,737,544,000		10,643,036,000	10,882,717,000			10,737,544,000	10,643,036,000	10,882,717,000	10,644,432,000	10,537,455,000	10,824,505,000
Allowance for loan losses	286,611,000	289,549,000	292,971,000	299,489,000			(286,611,000)	(292,971,000)	(299,489,000)	0	0	0
Net loans	10,450,933,000		10,350,065,000	10,583,228,000			10,450,933,000	10,350,065,000	10,583,228,000	10,644,432,000	10,537,455,000	10,824,505,000
Mortgage servicing rights	109,192,000	120,345,000	115,723,000	98,942,000	119,066,000	73,824,000	109,192,000	115,723,000	98,942,000	109,192,000	115,723,000	98,942,000
Derivative contracts, assets	229,887,000		270,445,000	334,576,000			229,887,000	270,445,000	334,576,000	229,887,000	270,445,000	334,576,000
Other assets - private equity funds							28,313,000	25,436,000	23,834,000	28,313,000	25,436,000	23,834,000
Deposits with no stated maturity							13,951,177,000	13,669,893,000	12,414,412,000	13,951,177,000	13,669,893,000	12,414,412,000
Time deposits	3,634,700,000		3,509,168,000	3,673,088,000			3,634,700,000	3,509,168,000	3,673,088,000	3,655,527,000	2,979,505,000	3,158,578,000
Other borrowings							2,962,759,000	3,117,358,000	3,970,770,000	2,962,773,000	2,982,460,000	3,834,960,000
Subordinated debentures	398,788,000		398,701,000	398,617,000			398,788,000	398,701,000	398,617,000	412,242,000	413,328,000	415,161,000
Derivative contracts, liabilities	173,917,000		215,420,000	299,851,000			173,917,000	215,420,000	299,851,000	173,917,000	215,420,000	299,851,000
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Contractual Yield Range, Minimum (in hundredths)													0.25%	0.25%	0.25%	0.38%	0.38%	0.38%	0.25%	0.38%	0.38%	0.38%	0.38%	0.38%	0.01%	0.01%	0.01%	0.07%	0.14%	0.13%	5.19%	5.19%	5.19%
Contractual Yield Range, Maximum (in hundredths)													18.00%	18.00%	18.00%	18.00%	18.00%	18.00%	18.00%	18.00%	18.00%	21.00%	21.00%	21.00%	9.64%	9.64%	9.64%	6.58%	6.58%	6.58%	5.82%	5.82%	5.82%
Average Re-pricing (in years)													0.6	0.54	0.57	1.18	1.08	1.17	3.32	3.12	3.65	0.53	0.90	0.67	1.91	1.54	1.85	0	0.37	0.02	1.87	2.6	2.30
Discount Rate Range, Minimum (in hundredths)													0.72%	0.72%	0.72%	0.28%	0.30%	0.29%	0.74%	1.16%	0.79%	1.96%	1.92%	1.98%	0.76%	1.05%	0.82%	0.07%	0.18%	0.13%
Discount Rate Range, Maximum (in hundredths)													4.50%	4.61%	4.67%	3.66%	3.91%	3.81%	4.31%	4.17%	4.58%	3.74%	4.16%	3.91%	1.45%	1.54%	1.56%	2.65%	2.81%	2.73%
Discount Rate (in hundredths)																															3.50%	3.88%	3.72%
Allowance for loan losses excluding loans held for sale	$ 259,000,000		$ 266,000,000	$ 280,000,000