Derivatives (Narrative) (Details) (USD $)	3 Months Ended		6 Months Ended															3 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012	Jun. 30, 2013 Visa Class B Shares [Member]	Jun. 30, 2012 Visa Class B Shares [Member]	Jun. 30, 2013 Parent Company [Member]	Jun. 30, 2012 Parent Company [Member]	Jun. 30, 2013 Derivative Instruments With Accelerated Termination Provisions [Member]	Jun. 30, 2012 Derivative Instruments With Accelerated Termination Provisions [Member]	Jun. 30, 2013 Long Term Debt Hedged With Fair Value Interest Rate Derivatives Using Long Haul Method [Member]	Jun. 30, 2012 Long Term Debt Hedged With Fair Value Interest Rate Derivatives Using Long Haul Method [Member]	Jun. 30, 2013 Subordinated Debentures Subject To Mandatory Redemption Amount [Member]	Oct. 31, 2012 Subordinated Debentures Subject To Mandatory Redemption Amount [Member]	Jun. 30, 2012 Subordinated Debentures Subject To Mandatory Redemption Amount [Member]	Apr. 30, 2012 Subordinated Debentures Subject To Mandatory Redemption Amount [Member]	Jun. 30, 2013 Hedge Of Held To Maturity Trust Preferred Loans [Member] Parent Company [Member]	Jun. 30, 2012 Hedge Of Held To Maturity Trust Preferred Loans [Member] Parent Company [Member]	Jun. 30, 2013 Additional Derivative Agreements [Member] Derivative Instruments With Adjustable Collateral Posting Thresholds [Member]	Jun. 30, 2012 Additional Derivative Agreements [Member] Derivative Instruments With Adjustable Collateral Posting Thresholds [Member]	Jun. 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]	Jun. 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	$ 111,900,000	$ 201,500,000	$ 111,900,000	$ 201,500,000
Collateral received										218,300,000	279,500,000									218,300,000	279,500,000
Collateral cash payables	93,100,000	148,400,000	93,100,000	148,400,000
Securities posted collateral										23,400,000	44,100,000									102,600,000	190,500,000
Net fair value of derivative assets with adjustable posting thresholds										148,700,000	245,700,000									148,800,000	247,200,000
Net fair value of derivative liabilities with adjustable posting thresholds										30,000,000	41,000,000									116,500,000	191,500,000
Total trading revenues	58,500,000	68,400,000	126,500,000	167,500,000
Certain term borrowings total												500,000,000	500,000,000									554,000,000	904,000,000
Net fair value of interest rate derivatives hedging												20,700,000	27,900,000									50,900,000	86,900,000
Noncallable senior debt maturing date			December 2015
Net fair value of interest rate derivatives hedging subordinated debt														18,700,000		1,100,000		1,100,000	5,000,000
Other Long-term Debt	1,800,255,000	2,294,224,000	1,800,255,000	2,294,224,000	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	166,800,000
Fixed rate term before conversion to floating rate																		5 years
Derivative liabilities related to sale						2,200,000	3,500,000
Hedged amount of foreign currency denominated loans	$ 600,000	$ 700,000	$ 600,000	$ 700,000