Cash and Cash Equivalents (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013		Sep. 30, 2013	Dec. 31, 2012
Cash and Cash Equivalents [Abstract]
Cash and due from banks	$ 1,815,581	[1]	$ 1,349,688	[1]
Securities purchased under agreements to resell	50,834	[2]	172,989	[2]
Other short-term investment securities	6,122		16,102
Total cash and cash equivalents	$ 1,872,537		$ 1,538,779		$ 1,942,744	$ 1,008,983

[1] At September 30, 2014 and December 31, 2013, $883 million and $715 million, respectively, of our cash and due from banks was deposited at the Federal Reserve Bank and was earning interest at the Federal Funds target rate, and interest-earning deposits in other financial institutions were $442 million and $300 million, respectively.

[2] At September 30, 2014 and December 31, 2013, securities purchased under agreements to resell were collateralized by U.S. Treasury securities and U.S. agency securities with aggregate fair values of $52 million and $176 million, respectively. None of these securities received as collateral were sold or repledged as of September 30, 2014 or December 31, 2013.