Investment Securities (Available For Sale Securities Unrealized Gains And Losses, By Security Type) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Investment [Line Items]
Amortized Cost	$ 8,721,015	$ 9,012,095
Gross Unrealized Gains	314,542	238,507
Gross Unrealized Losses	(14,606)	(25,900)
Fair Value	9,020,951	9,224,702
U.S. Government And Federal Agency Obligations [Member]
Investment [Line Items]
Amortized Cost	324,475	328,530
Gross Unrealized Gains	43,022	36,135
Gross Unrealized Losses	0	0
Fair Value	367,497	364,665
Government-Sponsored Enterprise Obligations [Member]
Investment [Line Items]
Amortized Cost	374,525	311,529
Gross Unrealized Gains	5,678	4,169
Gross Unrealized Losses	(13)	0
Fair Value	380,190	315,698
State And Municipal Obligations [Member]
Investment [Line Items]
Amortized Cost	1,426,059	1,220,840
Gross Unrealized Gains	48,313	35,663
Gross Unrealized Losses	(13,121)	(11,219)
Fair Value	1,461,251	1,245,284
Agency Mortgage-Backed Securities [Member]
Investment [Line Items]
Amortized Cost	3,311,100	3,989,464
Gross Unrealized Gains	160,215	117,088
Gross Unrealized Losses	(53)	(493)
Fair Value	3,471,262	4,106,059
Non-Agency Mortgage-Backed Securities [Member]
Investment [Line Items]
Amortized Cost	241,657	315,752
Gross Unrealized Gains	13,698	8,962
Gross Unrealized Losses	(183)	(7,812)
Fair Value	255,172	316,902
Asset-Backed Securities [Member]
Investment [Line Items]
Amortized Cost	2,917,206	2,692,436
Gross Unrealized Gains	14,840	7,083
Gross Unrealized Losses	(1,236)	(6,376)
Fair Value	2,930,810	2,693,143
Other Debt Securities [Member]
Investment [Line Items]
Amortized Cost	117,510	135,190
Gross Unrealized Gains	4,113	6,070
Gross Unrealized Losses	0	0
Fair Value	121,623	141,260
Equity Securities [Member]
Investment [Line Items]
Amortized Cost	8,483	18,354
Gross Unrealized Gains	24,663	23,337
Gross Unrealized Losses	0	0
Fair Value	33,146	41,691
Total Mortgage And Asset-Backed Securities [Member]
Investment [Line Items]
Amortized Cost	6,469,963	6,997,652
Gross Unrealized Gains	188,753	133,133
Gross Unrealized Losses	(1,472)	(14,681)
Fair Value	$ 6,657,244	$ 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

- 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