Derivatives (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended															3 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Sep. 30, 2013 Visa Class B Shares [Member]	Sep. 30, 2012 Visa Class B Shares [Member]	Sep. 30, 2013 Parent Company [Member]	Sep. 30, 2012 Parent Company [Member]	Sep. 30, 2013 Derivative Instruments With Accelerated Termination Provisions [Member]	Sep. 30, 2012 Derivative Instruments With Accelerated Termination Provisions [Member]	Sep. 30, 2013 Long Term Debt Hedged With Fair Value Interest Rate Derivatives Using Long Haul Method [Member]	Sep. 30, 2012 Long Term Debt Hedged With Fair Value Interest Rate Derivatives Using Long Haul Method [Member]	Sep. 30, 2013 Subordinated Debentures Subject To Mandatory Redemption Amount [Member]	Oct. 31, 2012 Subordinated Debentures Subject To Mandatory Redemption Amount [Member]	Sep. 30, 2012 Subordinated Debentures Subject To Mandatory Redemption Amount [Member]	Apr. 30, 2012 Subordinated Debentures Subject To Mandatory Redemption Amount [Member]	Sep. 30, 2013 Hedge Of Held To Maturity Trust Preferred Loans [Member] Parent Company [Member]	Sep. 30, 2012 Hedge Of Held To Maturity Trust Preferred Loans [Member] Parent Company [Member]	Sep. 30, 2013 Additional Derivative Agreements [Member] Derivative Instruments With Adjustable Collateral Posting Thresholds [Member]	Sep. 30, 2012 Additional Derivative Agreements [Member] Derivative Instruments With Adjustable Collateral Posting Thresholds [Member]	Sep. 30, 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]	Sep. 30, 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	$ 111,700,000	$ 197,400,000	$ 111,700,000	$ 197,400,000
Collateral received										213,200,000	288,800,000									213,200,000	288,800,000
Collateral cash payables	90,100,000	153,300,000	90,100,000	153,300,000
Securities posted collateral										24,400,000	46,400,000									102,500,000	188,200,000
Net fair value of derivative assets with adjustable posting thresholds										144,500,000	255,800,000									144,500,000	256,300,000
Net fair value of derivative liabilities with adjustable posting thresholds										27,100,000	41,900,000									110,300,000	187,500,000
Total trading revenues	54,400,000	74,500,000	180,900,000	242,000,000
Certain term borrowings total												500,000,000	500,000,000									554,000,000	904,000,000
Net fair value of interest rate derivatives hedging												20,000,000	29,500,000			400,000						46,100,000	81,300,000
Noncallable senior debt maturing date			2015-12-01
Net fair value of interest rate derivatives hedging subordinated debt														19,600,000				1,100,000	3,400,000
Other Long-term Debt	1,771,288,000	2,263,238,000	1,771,288,000	2,263,238,000	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								6,500,000	128,800,000
Fixed rate term before conversion to floating rate																		5 years
Derivative liabilities related to sale						2,700,000	2,300,000
Hedged amount of foreign currency denominated loans	$ 600,000	$ 700,000	$ 600,000	$ 700,000