Securities Sold Under Agreements To Repurchase And Other Borrowings (Summary Of Securities Sold Under Agreements To Repurchase And Other Borrowings) (Detail) (USD $)	Sep. 30, 2014		Dec. 31, 2013
Securities Sold Under Agreements to Repurchase and Other Short-term Borrowings [Line Items]
Securities sold under agreements to repurchase:	$ 948,975,000		$ 1,009,662,000
Federal funds purchased	288,000,000		322,000,000
Securities sold under agreements to repurchase and other borrowings	1,236,975,000		1,331,662,000
Gross repurchase agreement liability	900,000,000
Original maturity of one year or less [Member]
Securities Sold Under Agreements to Repurchase and Other Short-term Borrowings [Line Items]
Securities sold under agreements to repurchase:	398,975,000		359,662,000
Original maturity of greater than one year, non-callable [Member]
Securities Sold Under Agreements to Repurchase and Other Short-term Borrowings [Line Items]
Securities sold under agreements to repurchase:	550,000,000		550,000,000
Callable at the option of the counterparty [Member]
Securities Sold Under Agreements to Repurchase and Other Short-term Borrowings [Line Items]
Securities sold under agreements to repurchase:	$ 0	[1]	$ 100,000,000	[1]

[1] There were $100 million of securities sold under agreements to repurchase that had callable options for June 23, 2014 and were classified as callable at the option of the counterparty at December 31, 2013. The callable options were not exercised as of the call date and were reclassified as original maturity of greater than one year, non-callable during the quarter ended September 30, 2014.