Loans Past Due Status for Loans Held-In-Portfolio (Net of Unearned Income) Including Covered Loans (Detail) (USD $) In Thousands	Jun. 30, 2011		Dec. 31, 2010
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held-in-portfolio	$ 25,274,269	[1]	$ 25,564,917	[2]
Covered under Loss Sharing Agreements with FDIC
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due 30-59 Days	141,748		233,675
Past Due 60-89 Days	87,769		146,180
Past Due 90 Days or More	1,176,896		953,284
Total Past Due	1,406,413		1,333,139
Current	3,210,162		3,503,743
Loans held-in-portfolio	4,616,575	[1]	4,836,882	[2]
Covered under Loss Sharing Agreements with FDIC | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due 30-59 Days	48,627		108,244
Past Due 60-89 Days	33,921		89,403
Past Due 90 Days or More	471,955		434,956
Total Past Due	554,503		632,603
Current	1,782,886		1,830,946
Loans held-in-portfolio	2,337,389		2,463,549
Covered under Loss Sharing Agreements with FDIC | Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due 30-59 Days	7,529		12,091
Past Due 60-89 Days	6,719		5,491
Past Due 90 Days or More	23,928		32,585
Total Past Due	38,176		50,167
Current	220,200		253,465
Loans held-in-portfolio	258,376		303,632
Covered under Loss Sharing Agreements with FDIC | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due 30-59 Days	14,068		23,445
Past Due 60-89 Days	12,180		11,906
Past Due 90 Days or More	459,613		351,386
Total Past Due	485,861		386,737
Current	159,299		253,755
Loans held-in-portfolio	645,160		640,492
Covered under Loss Sharing Agreements with FDIC | Mortgages
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due 30-59 Days	63,582		80,978
Past Due 60-89 Days	31,156		34,897
Past Due 90 Days or More	204,098		119,745
Total Past Due	298,836		235,620
Current	939,392		1,023,839
Loans held-in-portfolio	1,238,228		1,259,459
Covered under Loss Sharing Agreements with FDIC | Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due 30-59 Days	7,942		8,917
Past Due 60-89 Days	3,793		4,483
Past Due 90 Days or More	17,302		14,612
Total Past Due	29,037		28,012
Current	108,385		141,738
Loans held-in-portfolio	137,422		169,750
Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held-in-portfolio	9,178,167		9,470,225
Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held-in-portfolio	4,153,931		4,690,441
Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held-in-portfolio	1,038,919		1,141,343
Mortgages
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held-in-portfolio	6,585,740		5,784,181
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans held-in-portfolio	$ 3,731,456

[1] Loans held-in-portfolio at June 30, 2011 are net of $ 104 million in unearned income and exclude $ 509 million in loans held-for-sale.

[2] Loans held-in-portfolio at December 31, 2010 are net of $106 million in unearned income and exclude $894 million in loans held-for-sale.