Fair Value (Schedule Of Carrying Values And Estimated Fair Values Of Financial Instruments) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]
Held-to-maturity, fair value	$ 727,908	$ 674,741
Time deposits	2,689,688	2,962,931
Other short-term borrowings	0	5,409
Long-term debt (less fair value hedges)	2,304,301	2,337,113
Carrying Value [Member]
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]
Held-to-maturity, fair value	777,849	756,909
Loans and leases (including loans held for sale), net of allowance	37,590,017	37,020,811
Time deposits	2,689,688	2,962,931
Foreign deposits	1,607,409	1,804,060
Other short-term borrowings	0	5,409
Long-term debt (less fair value hedges)	2,298,853	2,329,323
Estimated Fair Value [Member]
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]
Held-to-maturity, fair value	727,908	674,741
Loans and leases (including loans held for sale), net of allowance	37,402,157	37,024,198
Time deposits	2,703,085	2,988,714
Foreign deposits	1,607,052	1,803,625
Other short-term borrowings	0	5,421
Long-term debt (less fair value hedges)	$ 2,529,021	$ 2,636,422