Investment Securities (Summary Of Available For Sale Investment Securities By Maturity Groupings) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Investment [Line Items]
Amortized Cost	$ 8,896,396	$ 9,012,095
Available for sale investment securities	9,120,399	9,224,702
U.S. Government And Federal Agency Obligations [Member]
Investment [Line Items]
Amortized Cost	328,781	328,530
Available for sale investment securities	368,662	364,665
U.S. Government And Federal Agency Obligations [Member] \| Available-For-Sale Securities, Maturity Within 1 Year [Member]
Investment [Line Items]
Amortized Cost	7,856
Available for sale investment securities	8,011
U.S. Government And Federal Agency Obligations [Member] \| Available-For-Sale Securities, Maturity After 1 But Within 5 Years [Member]
Investment [Line Items]
Amortized Cost	186,985
Available for sale investment securities	208,287
U.S. Government And Federal Agency Obligations [Member] \| Available-For-Sale Securities, Maturity After 5 But Within 10 Years [Member]
Investment [Line Items]
Amortized Cost	133,940
Available for sale investment securities	152,364
Government-Sponsored Enterprise Obligations [Member]
Investment [Line Items]
Amortized Cost	275,112	311,529
Available for sale investment securities	277,924	315,698
Government-Sponsored Enterprise Obligations [Member] \| Available-For-Sale Securities, Maturity Within 1 Year [Member]
Investment [Line Items]
Amortized Cost	31,111
Available for sale investment securities	31,230
Government-Sponsored Enterprise Obligations [Member] \| Available-For-Sale Securities, Maturity After 1 But Within 5 Years [Member]
Investment [Line Items]
Amortized Cost	108,983
Available for sale investment securities	112,296
Government-Sponsored Enterprise Obligations [Member] \| Available-For-Sale Securities, Maturity After 5 But Within 10 Years [Member]
Investment [Line Items]
Amortized Cost	12,114
Available for sale investment securities	12,219
Government-Sponsored Enterprise Obligations [Member] \| Available-For-Sale Securities, Maturity After 10 Years [Member]
Investment [Line Items]
Amortized Cost	122,904
Available for sale investment securities	122,179
State And Municipal Obligations [Member]
Investment [Line Items]
Amortized Cost	1,307,844	1,220,840
Available for sale investment securities	1,326,867	1,245,284
State And Municipal Obligations [Member] \| Available-For-Sale Securities, Maturity Within 1 Year [Member]
Investment [Line Items]
Amortized Cost	82,630
Available for sale investment securities	83,542
State And Municipal Obligations [Member] \| Available-For-Sale Securities, Maturity After 1 But Within 5 Years [Member]
Investment [Line Items]
Amortized Cost	542,924
Available for sale investment securities	561,698
State And Municipal Obligations [Member] \| Available-For-Sale Securities, Maturity After 5 But Within 10 Years [Member]
Investment [Line Items]
Amortized Cost	471,973
Available for sale investment securities	484,430
State And Municipal Obligations [Member] \| Available-For-Sale Securities, Maturity After 10 Years [Member]
Investment [Line Items]
Amortized Cost	210,317
Available for sale investment securities	197,197
Mortgage And Asset-Backed Securities [Member] \| Agency Mortgage-Backed Securities [Member]
Investment [Line Items]
Amortized Cost	3,742,525
Available for sale investment securities	3,866,456
Mortgage And Asset-Backed Securities [Member] \| Non-Agency Mortgage-Backed Securities [Member]
Investment [Line Items]
Amortized Cost	287,375
Available for sale investment securities	294,221
Mortgage And Asset-Backed Securities [Member] \| Asset-Backed Securities [Member]
Investment [Line Items]
Amortized Cost	2,815,676
Available for sale investment securities	2,817,492
Other Debt Securities [Member]
Investment [Line Items]
Amortized Cost	117,831	135,190
Available for sale investment securities	123,355	141,260
Other Debt Securities [Member] \| Available-For-Sale Securities, Maturity Within 1 Year [Member]
Investment [Line Items]
Amortized Cost	47,999
Available for sale investment securities	49,544
Other Debt Securities [Member] \| Available-For-Sale Securities, Maturity After 1 But Within 5 Years [Member]
Investment [Line Items]
Amortized Cost	63,858
Available for sale investment securities	67,837
Other Debt Securities [Member] \| Available-For-Sale Securities, Maturity After 5 But Within 10 Years [Member]
Investment [Line Items]
Amortized Cost	5,974
Available for sale investment securities	5,974
Equity Securities [Member]
Investment [Line Items]
Amortized Cost	21,252	18,354
Available for sale investment securities	45,422	41,691
Agency Mortgage-Backed Securities [Member]
Investment [Line Items]
Amortized Cost	3,742,525	3,989,464
Available for sale investment securities	3,866,456	4,106,059
Non-Agency Mortgage-Backed Securities [Member]
Investment [Line Items]
Amortized Cost	287,375	315,752
Available for sale investment securities	294,221	316,902
Total Mortgage And Asset-Backed Securities [Member]
Investment [Line Items]
Amortized Cost	6,845,576	6,997,652
Available for sale investment securities	$ 6,978,169	$ 7,116,104

For an unclassified balance sheet, this item represents investments in debt and equity securities which are categorized neither as held-to-maturity nor trading.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 12

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

-Paragraph 15E

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 22

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

-Paragraph 15D

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 13

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

-Paragraph 15C

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 14

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 9: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 16

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 10: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6379932&loc=d3e22054-111558

+ Details

- Definition

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References+ Details