Loans and Allowance for Credit Losses Summary Of Gross Loans (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans before unearned income	$ 11,975,964,000	$ 11,940,505,000
Unearned income	(6,994,000)	(7,198,000)
Loans, net of unearned income	11,968,970,000	11,933,307,000
Loans and Leases Receivable, Related Parties	167,400,000	201,100,000
Proceeds from Related Party Debt	29,500,000
Repayments of Related Party Debt	63,200,000
Loans Serviced By Unrelated Third Party	3,900,000,000	3,400,000,000
Real-estate commercial mortage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans before unearned income	4,602,596,000	4,375,980,000
Loans, net of unearned income	4,602,596,000	4,375,980,000
Commercial - industrial, financial, and agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans before unearned income	3,639,368,000	3,704,384,000
Loans, net of unearned income	3,639,368,000	3,704,384,000
Real-estate - home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans before unearned income	1,624,562,000	1,641,777,000
Loans, net of unearned income	1,624,562,000	1,641,777,000
Real-estate - residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans before unearned income	1,097,192,000	995,990,000
Loans, net of unearned income	1,097,192,000	995,990,000
Real-estate - construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans before unearned income	615,445,000	801,185,000
Loans, net of unearned income	615,445,000	801,185,000
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans before unearned income	318,101,000	350,161,000
Loans, net of unearned income	318,101,000	350,161,000
Leasing and other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans before unearned income	63,254,000	61,017,000
Overdrafts [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans before unearned income	$ 15,446,000	$ 10,011,000