Summary of Borrowed Funds (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Debt Outstanding [Line Items]
FHLB advances	$ 10,872,576	$ 8,842,974
Repurchase agreements	3,425,000	4,125,000
Federal funds purchased	445,000	100,000	0
Total wholesale borrowings	14,742,576	13,067,974
Junior subordinated debentures	358,126	357,917
Preferred stock of subsidiaries	4,300	4,300
Total other borrowings	362,426	362,217
Total borrowed funds	$ 15,105,002	$ 13,430,191