Condensed Consolidating Statement of Condition (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011	Dec. 31, 2010
Assets
Cash And Due From Banks	$ 477,342	$ 535,282	$ 567,141	$ 452,373
Money market investments	925,663	1,376,174
Trading Securities	226,918	436,331
Available For Sale Securities	5,120,301	5,009,823
Investment securities held-to-maturity, at amortized cost	122,072	125,383
Other investment securities, at lower of cost or realizable value	213,389	179,880
Loans held-for-sale, at lower of cost or fair value	337,049	363,093
Loans held-in-portfolio:
Less- Unearned Income	97,255	100,596
Allowance for loan losses	761,172	815,308
Total loans held-in-portfolio, net	23,896,548	24,135,991
FDIC loss share asset	1,559,057	1,915,128	1,895,059	2,410,219
Premises and equipment, net	525,733	538,486
Interest Receivable	133,943	125,209
Servicing Asset At Fair Value Amount	158,367	151,323	157,226	166,907
Other Assets	1,724,927	1,462,393
Goodwill	647,757	648,350	648,353	647,387
Intangible Assets Net Excluding Goodwill	56,762	63,954
Total assets	36,503,366	37,348,432
Deposits Abstract
Noninterest Bearing Deposit Liabilities	5,404,470	5,655,474
Interest Bearing Deposit Liabilities	20,915,029	22,286,653
Total deposits	26,319,499	27,942,127
Securities Sold under Agreements to Repurchase	1,944,564	2,141,097
Other short-term borrowings	1,206,200	296,200
Notes Payable	1,866,377	1,856,372
Other liabilities	1,097,742	1,193,883
Liabilities	32,434,382	33,429,679
Stockholders Equity Abstract
Preferred stock	50,160	50,160
Common stock	1,031	1,026
Surplus	4,131,681	4,123,898
Accumulated deficit	(54,183)	(212,726)
Treasury stock	(270)	(1,057)
Accumulated other comprehensive (loss) income, net of tax	(59,435)	(42,548)
Total stockholders' equity	4,068,984	3,918,753	4,012,601	3,800,531
Liabilities And Stockholders Equity	36,503,366	37,348,432
Non Covered Under Loss Sharing Agreements With F D I C [Member]
Loans held-in-portfolio:
Loans held-in-portfolio	20,851,108	20,703,192
Real Estate Acquired Through Foreclosure	252,024	172,497
Covered Under Loss Sharing Agreements With F D I C [Member]
Loans held-in-portfolio:
Loans held-in-portfolio	3,903,867	4,348,703
Real Estate Acquired Through Foreclosure	125,514	109,135
Parent Company [Member]
Assets
Cash And Due From Banks	4,177	6,365	1,478	1,638
Money market investments	18,337	42,239
Trading Securities	0	0
Available For Sale Securities	41,193	35,700
Investment securities held-to-maturity, at amortized cost	185,000	185,000
Other investment securities, at lower of cost or realizable value	10,850	10,850
Investment in subsidiaries	4,209,097	3,987,287
Loans held-for-sale, at lower of cost or fair value	0	0
Loans held-in-portfolio:
Less- Unearned Income	0	0
Allowance for loan losses	190	8
Total loans held-in-portfolio, net	320,382	249,607
FDIC loss share asset	0	0
Premises and equipment, net	2,661	2,533
Interest Receivable	2,680	1,512
Servicing Asset At Fair Value Amount	0	0
Other Assets	102,847	217,877
Goodwill	0	0
Intangible Assets Net Excluding Goodwill	553	554
Total assets	4,897,777	4,739,524
Deposits Abstract
Noninterest Bearing Deposit Liabilities	0	0
Interest Bearing Deposit Liabilities	0	0
Total deposits	0	0
Securities Sold under Agreements to Repurchase	0	0
Other short-term borrowings	0	0
Notes Payable	782,474	760,849
Subordinated Debt	0	0
Other liabilities	46,319	59,922
Liabilities	828,793	820,771
Stockholders Equity Abstract
Preferred stock	50,160	50,160
Common stock	1,031	1,026
Surplus	4,123,154	4,115,371
Accumulated deficit	(45,656)	(204,199)
Treasury stock	(270)	(1,057)
Accumulated other comprehensive (loss) income, net of tax	(59,435)	(42,548)
Total stockholders' equity	4,068,984	3,918,753
Liabilities And Stockholders Equity	4,897,777	4,739,524
Parent Company [Member] | Non Covered Under Loss Sharing Agreements With F D I C [Member]
Loans held-in-portfolio:
Loans held-in-portfolio	320,572	249,615
Real Estate Acquired Through Foreclosure	0	0
Parent Company [Member] | Covered Under Loss Sharing Agreements With F D I C [Member]
Loans held-in-portfolio:
Loans held-in-portfolio	0	0
Real Estate Acquired Through Foreclosure	0	0
Non Guarantor Subsidiaries Member
Assets
Cash And Due From Banks	626	932	271	1,576
Money market investments	640	552
Trading Securities	0	0
Available For Sale Securities	0	0
Investment securities held-to-maturity, at amortized cost	0	0
Other investment securities, at lower of cost or realizable value	4,492	4,492
Investment in subsidiaries	1,643,820	1,627,313
Loans held-for-sale, at lower of cost or fair value	0	0
Loans held-in-portfolio:
Less- Unearned Income	0	0
Allowance for loan losses	0	0
Total loans held-in-portfolio, net	0	0
FDIC loss share asset	0	0
Premises and equipment, net	116	118
Interest Receivable	31	113
Servicing Asset At Fair Value Amount	0	0
Other Assets	12,553	13,222
Goodwill	0	0
Intangible Assets Net Excluding Goodwill	0	0
Total assets	1,662,278	1,646,742
Deposits Abstract
Noninterest Bearing Deposit Liabilities	0	0
Interest Bearing Deposit Liabilities	0	0
Total deposits	0	0
Securities Sold under Agreements to Repurchase	0	0
Other short-term borrowings	1,000	30,500
Notes Payable	427,381	427,297
Subordinated Debt	0	0
Other liabilities	44,777	42,269
Liabilities	473,158	500,066
Stockholders Equity Abstract
Preferred stock	0	0
Common stock	2	2
Surplus	4,153,208	4,103,208
Accumulated deficit	(3,019,127)	(3,013,481)
Treasury stock	0	0
Accumulated other comprehensive (loss) income, net of tax	55,037	56,947
Total stockholders' equity	1,189,120	1,146,676
Liabilities And Stockholders Equity	1,662,278	1,646,742
Non Guarantor Subsidiaries Member | Non Covered Under Loss Sharing Agreements With F D I C [Member]
Loans held-in-portfolio:
Loans held-in-portfolio	0	0
Real Estate Acquired Through Foreclosure	0	0
Non Guarantor Subsidiaries Member | Covered Under Loss Sharing Agreements With F D I C [Member]
Loans held-in-portfolio:
Loans held-in-portfolio	0	0
Real Estate Acquired Through Foreclosure	0	0
Other Subsidiaries [Member]
Assets
Cash And Due From Banks	477,537	534,796	567,336	451,723
Money market investments	907,326	1,357,996
Trading Securities	226,918	436,331
Available For Sale Securities	5,096,076	4,991,760
Investment securities held-to-maturity, at amortized cost	122,072	125,383
Other investment securities, at lower of cost or realizable value	198,047	164,538
Investment in subsidiaries	0	0
Loans held-for-sale, at lower of cost or fair value	337,049	363,093
Loans held-in-portfolio:
Less- Unearned Income	97,255	100,596
Allowance for loan losses	760,982	815,300
Total loans held-in-portfolio, net	23,866,899	24,106,359
FDIC loss share asset	1,559,057	1,915,128
Premises and equipment, net	522,956	535,835
Interest Receivable	131,588	123,859
Servicing Asset At Fair Value Amount	158,367	151,323
Other Assets	1,633,355	1,261,324
Goodwill	647,757	648,350
Intangible Assets Net Excluding Goodwill	56,209	63,400
Total assets	36,318,751	37,061,107
Deposits Abstract
Noninterest Bearing Deposit Liabilities	5,409,909	5,688,643
Interest Bearing Deposit Liabilities	20,936,879	22,287,448
Total deposits	26,346,788	27,976,091
Securities Sold under Agreements to Repurchase	1,944,564	2,165,157
Other short-term borrowings	1,470,000	459,600
Notes Payable	656,522	668,226
Subordinated Debt	185,000	185,000
Other liabilities	1,052,530	1,138,702
Liabilities	31,655,404	32,592,776
Stockholders Equity Abstract
Preferred stock	0	0
Common stock	55,628	55,627
Surplus	8,799,459	5,859,773
Accumulated deficit	(4,129,950)	(1,403,925)
Treasury stock	0	0
Accumulated other comprehensive (loss) income, net of tax	(61,790)	(43,144)
Total stockholders' equity	4,663,347	4,468,331
Liabilities And Stockholders Equity	36,318,751	37,061,107
Other Subsidiaries [Member] | Non Covered Under Loss Sharing Agreements With F D I C [Member]
Loans held-in-portfolio:
Loans held-in-portfolio	20,821,269	20,673,552
Real Estate Acquired Through Foreclosure	252,024	172,497
Other Subsidiaries [Member] | Covered Under Loss Sharing Agreements With F D I C [Member]
Loans held-in-portfolio:
Loans held-in-portfolio	3,903,867	4,348,703
Real Estate Acquired Through Foreclosure	125,514	109,135
Consolidation Eliminations Member
Assets
Cash And Due From Banks	(4,998)	(6,811)	(1,944)	(2,564)
Money market investments	(640)	(24,613)
Trading Securities	0	0
Available For Sale Securities	(16,968)	(17,637)
Investment securities held-to-maturity, at amortized cost	(185,000)	(185,000)
Other investment securities, at lower of cost or realizable value	0	0
Investment in subsidiaries	(5,852,917)	(5,614,600)
Loans held-for-sale, at lower of cost or fair value	0	0
Loans held-in-portfolio:
Less- Unearned Income	0	0
Allowance for loan losses	0	0
Total loans held-in-portfolio, net	(290,733)	(219,975)
FDIC loss share asset	0	0
Premises and equipment, net	0	0
Interest Receivable	(356)	(275)
Servicing Asset At Fair Value Amount	0	0
Other Assets	(23,828)	(30,030)
Goodwill	0	0
Intangible Assets Net Excluding Goodwill	0	0
Total assets	(6,375,440)	(6,098,941)
Deposits Abstract
Noninterest Bearing Deposit Liabilities	(5,439)	(33,169)
Interest Bearing Deposit Liabilities	(21,850)	(795)
Total deposits	(27,289)	(33,964)
Securities Sold under Agreements to Repurchase	0	(24,060)
Other short-term borrowings	(264,800)	(193,900)
Notes Payable	0	0
Subordinated Debt	(185,000)	(185,000)
Other liabilities	(45,884)	(47,010)
Liabilities	(522,973)	(483,934)
Stockholders Equity Abstract
Preferred stock	0	0
Common stock	(55,630)	(55,629)
Surplus	(12,944,140)	(9,954,454)
Accumulated deficit	7,140,550	4,408,879
Treasury stock	0	0
Accumulated other comprehensive (loss) income, net of tax	6,753	(13,803)
Total stockholders' equity	(5,852,467)	(5,615,007)
Liabilities And Stockholders Equity	(6,375,440)	(6,098,941)
Consolidation Eliminations Member | Non Covered Under Loss Sharing Agreements With F D I C [Member]
Loans held-in-portfolio:
Loans held-in-portfolio	(290,733)	(219,975)
Real Estate Acquired Through Foreclosure	0	0
Consolidation Eliminations Member | Covered Under Loss Sharing Agreements With F D I C [Member]
Loans held-in-portfolio:
Loans held-in-portfolio	0	0
Real Estate Acquired Through Foreclosure	$ 0	$ 0