Investment Securities (Available For Sale Securities Unrealized Gains And Losses, By Security Type) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Investment [Line Items]
Amortized Cost	$ 8,493,793	$ 9,258,525
Gross Unrealized Gains	184,282	283,894
Gross Unrealized Losses	(100,793)	(20,171)
Fair Value	8,577,282	9,522,248
U.S. Government And Federal Agency Obligations [Member]
Investment [Line Items]
Amortized Cost	402,404	399,971
Gross Unrealized Gains	23,567	40,395
Gross Unrealized Losses	(10,466)	(1,607)
Fair Value	415,505	438,759
Government-Sponsored Enterprise Obligations [Member]
Investment [Line Items]
Amortized Cost	440,937	467,063
Gross Unrealized Gains	2,458	5,188
Gross Unrealized Losses	(18,433)	(677)
Fair Value	424,962	471,574
State And Municipal Obligations [Member]
Investment [Line Items]
Amortized Cost	1,608,969	1,585,926
Gross Unrealized Gains	29,756	46,076
Gross Unrealized Losses	(35,414)	(16,295)
Fair Value	1,603,311	1,615,707
Agency Mortgage-Backed Securities [Member]
Investment [Line Items]
Amortized Cost	2,755,358	3,248,007
Gross Unrealized Gains	74,070	132,953
Gross Unrealized Losses	(19,167)	(5)
Fair Value	2,810,261	3,380,955
Non-Agency Mortgage-Backed Securities [Member]
Investment [Line Items]
Amortized Cost	210,917	224,223
Gross Unrealized Gains	12,570	12,906
Gross Unrealized Losses	(1,406)	(118)
Fair Value	222,081	237,011
Asset-Backed Securities [Member]
Investment [Line Items]
Amortized Cost	2,893,173	3,152,913
Gross Unrealized Gains	7,603	15,848
Gross Unrealized Losses	(10,130)	(1,367)
Fair Value	2,890,646	3,167,394
Total Mortgage And Asset-Backed Securities [Member]
Investment [Line Items]
Amortized Cost	5,859,448	6,625,143
Gross Unrealized Gains	94,243	161,707
Gross Unrealized Losses	(30,703)	(1,490)
Fair Value	5,922,988	6,785,360
Other Debt Securities [Member]
Investment [Line Items]
Amortized Cost	166,612	174,727
Gross Unrealized Gains	971	3,127
Gross Unrealized Losses	(5,777)	(102)
Fair Value	161,806	177,752
Equity Securities [Member]
Investment [Line Items]
Amortized Cost	15,423	5,695
Gross Unrealized Gains	33,287	27,401
Gross Unrealized Losses	0	0
Fair Value	$ 48,710	$ 33,096

Amount of investment in debt and equity securities 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 Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=7534914&loc=d3e22054-111558

Reference 3: 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 4: 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 5: 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 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 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 8: 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 9: 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 10: 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.

+ 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

- Definition

This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

+ References+ Details