Loans And Allowance For Credit Losses (Summary Of Major Portfolio Segment And Specific Loan Class) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Loans And Allowance For Credit Losses [Abstract]
Loans held for sale	$ 114,810	$ 251,651
Commercial and industrial	11,904,477	11,256,945
Leasing	375,125	422,513
Owner occupied	7,378,586	7,589,082
Municipal	448,643	494,183
Total commercial	20,106,831	19,762,723
Construction and land development	2,240,295	1,939,413
Term	7,928,540	8,062,819
Total commercial real estate	10,168,835	10,002,232
Home equity credit line	2,124,328	2,177,680
1-4 family residential	4,636,895	4,350,329
Construction and other consumer real estate	321,436	321,235
Bankcard and other revolving plans	331,966	306,428
Other	207,578	216,379
Total consumer	7,622,203	7,372,051
FDIC-supported loans	374,861	528,241
Total loans	$ 38,272,730	$ 37,665,247