Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
ASSETS
Cash and due from banks	$ 1,341,319	$ 1,175,083
Money market investments:
Interest-bearing deposits	8,157,837	8,175,048
Federal funds sold and security resell agreements	379,947	282,248
Investment securities:
Held-to-maturity, at adjusted cost (approximate fair value $635,379 and $609,547)	606,279	588,981
Available-for-sale, at fair value	3,423,205	3,701,886
Trading account, at fair value	56,172	34,559
Marketable securities, total	4,085,656	4,325,426
Loans held for sale	126,344	171,328
Loans, net of unearned income and fees:
Loans and Leases Receivable, Net of Deferred Income	39,198,136	39,043,365
Less allowance for loan losses	736,953	746,291
Loans and Leases Receivable, Net Reported Amount, Covered and Not Covered	38,461,183	38,297,074
Other noninterest-bearing investments	848,775	855,642
Premises and equipment, net	785,519	726,372
Goodwill	1,014,129	1,014,129
Core deposit and other intangibles	33,562	36,444
Other real estate owned	39,248	46,105
Other assets	807,325	926,228
Total assets	56,080,844	56,031,127
LIABILITIES AND SHAREHOLDERS' EQUITY
Noninterest-bearing demand	19,257,889	18,758,753
Interest-bearing:
Savings and money market	23,097,351	23,029,928
Time	2,528,735	2,593,038
Foreign	1,648,111	1,980,161
Total deposits	46,532,086	46,361,880
Federal funds purchased and security repurchase agreements	279,837	340,348
Long-term debt	2,158,701	2,273,575
Reserve for unfunded lending commitments	88,693	89,705
Other liabilities	435,311	501,056
Total liabilities	49,494,628	49,566,564
Shareholders' equity:
Preferred stock, without par value, authorized 4,400,000 shares	1,003,970	1,003,970
Common stock, without par value; authorized 350,000,000 shares; issued and outstanding 184,895,182 and 184,677,696 shares	4,185,513	4,179,024
Retained earnings	1,542,195	1,473,670
Accumulated other comprehensive income (loss)	(145,462)	(192,101)
Total shareholders' equity	6,586,216	6,464,563
Total liabilities and shareholders' equity	$ 56,080,844	$ 56,031,127