Derivatives (Narrative) (Details) (USD $)	3 Months Ended															3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012	Mar. 31, 2013 Visa Class B Shares [Member]	Mar. 31, 2012 Visa Class B Shares [Member]	Mar. 31, 2013 Parent Company [Member]	Mar. 31, 2012 Parent Company [Member]	Mar. 31, 2013 Derivative Instruments With Accelerated Termination Provisions [Member]	Mar. 31, 2012 Derivative Instruments With Accelerated Termination Provisions [Member]	Mar. 31, 2013 Long Term Debt Hedged With Fair Value Interest Rate Derivatives Using Long Haul Method [Member]	Mar. 31, 2012 Long Term Debt Hedged With Fair Value Interest Rate Derivatives Using Long Haul Method [Member]	Mar. 31, 2013 Subordinated Debentures Subject To Mandatory Redemption Amount [Member]	Oct. 31, 2012 Subordinated Debentures Subject To Mandatory Redemption Amount [Member]	Apr. 30, 2012 Subordinated Debentures Subject To Mandatory Redemption Amount [Member]	Mar. 31, 2012 Subordinated Debentures Subject To Mandatory Redemption Amount [Member]	Mar. 31, 2013 Hedge Of Held To Maturity Trust Preferred Loans [Member] Parent Company [Member]	Mar. 31, 2012 Hedge Of Held To Maturity Trust Preferred Loans [Member] Parent Company [Member]	Mar. 31, 2013 Additional Derivative Agreements [Member] Derivative Instruments With Adjustable Collateral Posting Thresholds [Member]	Mar. 31, 2012 Additional Derivative Agreements [Member] Derivative Instruments With Adjustable Collateral Posting Thresholds [Member]	Mar. 31, 2013 Fixed Interest Rate Swaps To Hedge [Member] Long Term Debt Hedged With Fair Value Interest Rate Derivatives Using Shortcut Method [Member] Parent Company [Member]	Mar. 31, 2012 Fixed Interest Rate Swaps To Hedge [Member] Long Term Debt Hedged With Fair Value Interest Rate Derivatives Using Shortcut Method [Member] Parent Company [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Collateral cash receivables	$ 163,200,000	$ 184,800,000
Collateral received								255,300,000	278,600,000									255,300,000	278,600,000
Collateral cash payables	124,300,000	158,300,000
Securities posted collateral								37,800,000	40,800,000									153,900,000	175,300,000
Net fair value of derivative assets with adjustable posting thresholds								208,600,000	242,200,000									210,100,000	243,900,000
Net fair value of derivative liabilities with adjustable posting thresholds								35,800,000	37,500,000									156,400,000	172,900,000
Total trading revenues	68,000,000	99,100,000
Certain term borrowings total										500,000,000	500,000,000									904,000,000	904,000,000
Net fair value of interest rate derivatives hedging										24,600,000	25,400,000									60,500,000	92,600,000
Noncallable senior debt maturing date	December 2015
Net fair value of interest rate derivatives hedging subordinated debt												7,400,000			1,200,000	1,500,000	7,000,000
Other Long-term Debt	2,197,864,000	2,340,706,000	2,226,482,000									200,000,000	200,000,000	200,000,000	200,000,000
Hedged held-to-maturity trust preferred loans principal balance						21,500,000	196,300,000
Fixed rate term before conversion to floating rate																5 years
Derivative liabilities related to sale				2,100,000	2,900,000
Hedged amount of foreign currency denominated loans	$ 600,000	$ 700,000