Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
CASH FLOWS FROM OPERATING ACTIVITIES
Net income for the period	$ 89,403	$ 52,591
Adjustments to reconcile net income to net cash provided by operating activities:
Net impairment losses on investment securities	10,209	3,105
Provision for credit losses	11,960	50,460
Depreciation and amortization	57,143	89,806
Deferred income tax expense	19,685	53,790
Net increase (decrease) in trading securities	21,240	(7,882)
Net decrease in loans held for sale	20,913	28,471
Net write-down of and losses from sales of other real estate owned	7,832	19,750
Change in other liabilities	(18,799)	(36,824)
Change in other assets	50,425	18,154
Other, net	(21,916)	(2,200)
Net cash provided by operating activities	248,095	269,221
CASH FLOWS FROM INVESTING ACTIVITIES
Net increase in short term investments	(558,979)	(50,207)
Proceeds from maturities and paydowns of investment securities held-to-maturity	20,579	29,108
Purchases of investment securities held-to-maturity	(9,277)	(5,493)
Proceeds from sales, maturities, and paydowns of investment securities available-for-sale	440,982	302,250
Purchases of investment securities available-for-sale	(406,303)	(279,886)
Proceeds from sales of loans and leases	26,309	1,082
Net loan and lease collections (originations)	415,411	(44,811)
Net decrease in other noninterest-bearing investments	5,729	4,796
Net purchases of premises and equipment	(15,162)	(20,185)
Proceeds from sales of other real estate owned	39,399	91,841
Net cash paid for sale of branch	(22,568)
Net cash provided by (used in) investing activities	(63,880)	28,495
CASH FLOWS FROM FINANCING ACTIVITIES
Net increase (decrease) in deposits	252,837	(342,542)
Net change in short-term funds borrowed	(168,831)	80,092
Proceeds from issuance of long-term debt	332,750
Repayments of long-term debt	(141)	(156)
Cash paid for preferred stock redemption	(700,000)
Proceeds from issuance of common stock	342	25,212
Dividends paid on common and preferred stock	(40,796)	(34,601)
Other, net	(2,540)	(707)
Net cash used in financing activities	(326,379)	(272,702)
Net increase (decrease) in cash and due from banks	(142,164)	25,014
Cash and due from banks at beginning of period	1,224,350	924,126
Cash and due from banks at end of period	1,082,186	949,140
Cash paid for interest	62,789	91,281
Net cash refund received for income taxes	$ (21,668)	$ (108)