Investment Securities (Available For Sale Securities Unrealized Gains And Losses, By Security Type) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Amortized Cost	$ 9,012,095	$ 7,164,763
Gross Unrealized Gains	238,507	165,717
Gross Unrealized Losses	(25,900)	(36,177)
Fair Value	9,224,702	7,294,303
U.S. Government And Federal Agency Obligations [Member]
Amortized Cost	328,530	434,878
Gross Unrealized Gains	36,135	20,659
Fair Value	364,665	455,537
Government-Sponsored Enterprise Obligations [Member]
Amortized Cost	311,529	200,061
Gross Unrealized Gains	4,169	2,364
Gross Unrealized Losses		(530)
Fair Value	315,698	201,895
State And Municipal Obligations [Member]
Amortized Cost	1,220,840	1,117,020
Gross Unrealized Gains	35,663	19,108
Gross Unrealized Losses	(11,219)	(16,643)
Fair Value	1,245,284	1,119,485
Agency Mortgage-Backed Securities [Member]
Amortized Cost	3,989,464	2,437,123
Gross Unrealized Gains	117,088	57,516
Gross Unrealized Losses	(493)	(3,440)
Fair Value	4,106,059	2,491,199
Non-Agency Mortgage-Backed Securities [Member]
Amortized Cost	315,752	459,363
Gross Unrealized Gains	8,962	10,940
Gross Unrealized Losses	(7,812)	(14,513)
Fair Value	316,902	455,790
Asset-Backed Securities [Member]
Amortized Cost	2,692,436	2,342,866
Gross Unrealized Gains	7,083	12,445
Gross Unrealized Losses	(6,376)	(1,051)
Fair Value	2,693,143	2,354,260
Other Debt Securities [Member]
Amortized Cost	135,190	165,883
Gross Unrealized Gains	6,070	11,081
Fair Value	141,260	176,964
Equity Securities [Member]
Amortized Cost	18,354	7,569
Gross Unrealized Gains	23,337	31,604
Fair Value	41,691	39,173
Total Mortgage And Asset-Backed Securities [Member]
Amortized Cost	6,997,652	5,239,352
Gross Unrealized Gains	133,133	80,901
Gross Unrealized Losses	(14,681)	(19,004)
Fair Value	$ 7,116,104	$ 5,301,249

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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