Loans And Allowance For Credit Losses (Summary Of Major Portfolio Segment And Specific Loan Class) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Loans And Allowance For Credit Losses [Abstract]
Loans held for sale	$ 126,344	$ 171,328
Commercial and industrial	12,511,630	12,481,083
Leasing	389,576	387,929
Owner occupied	7,347,813	7,437,195
Municipal	482,074	449,418
Total commercial	20,731,093	20,755,625
Construction and land development	2,263,920	2,182,821
Term	8,080,348	8,005,837
Total commercial real estate	10,344,268	10,188,658
Home equity credit line	2,165,285	2,133,120
1-4 family residential	4,795,484	4,736,665
Construction and other consumer real estate	330,215	324,922
Bankcard and other revolving plans	360,389	356,240
Other	186,089	197,864
Total consumer	7,837,462	7,748,811
FDIC-supported loans	285,313	350,271
Total loans	$ 39,198,136	$ 39,043,365