Securities (Year End Securities Held To Maturity And Available For Sale) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Schedule Of Held-To-Maturity Securities and Available For Sale securities [Line Items]
Securities Held to Maturity, Amortized Cost	$ 365,996	$ 283,629
Securities Held to Maturity, Gross Unrealized Gains	38,465	13,653
Securities Held to Maturity, Gross Unrealized Losses		1,054
Securities Held to Maturity, Estimated Fair Value	404,461	296,228
Securities Available for Sale, Amortized Cost	7,440,389	5,009,759
Securities Available for Sale, Gross Unrealized Gains	349,514	170,374
Securities Available for Sale, Gross Unrealized Losses	203	22,663
Securities Available for Sale, Estimated Fair Value	7,789,700	5,157,470
U.S. Treasury [Member]
Schedule Of Held-To-Maturity Securities and Available For Sale securities [Line Items]
Securities Held to Maturity, Amortized Cost	247,797	247,421
Securities Held to Maturity, Gross Unrealized Gains	31,715	13,517
Securities Held to Maturity, Estimated Fair Value	279,512	260,938
Securities Available for Sale, Amortized Cost	2,020,621	973,033
Securities Available for Sale, Gross Unrealized Gains	36,111	13,998
Securities Available for Sale, Estimated Fair Value	2,056,732	987,031
US Government Agencies/Corporations [Member]
Schedule Of Held-To-Maturity Securities and Available For Sale securities [Line Items]
Securities Available for Sale, Amortized Cost	250,000
Securities Available for Sale, Gross Unrealized Gains	884
Securities Available for Sale, Estimated Fair Value	250,884
Residential Mortgage-Backed Securities Issued By U.S. Government Agencies And Corporations [Member]
Schedule Of Held-To-Maturity Securities and Available For Sale securities [Line Items]
Securities Held to Maturity, Amortized Cost	11,874	4,405
Securities Held to Maturity, Gross Unrealized Gains	153	136
Securities Held to Maturity, Estimated Fair Value	12,027	4,541
Securities Available for Sale, Amortized Cost	3,135,064	1,989,299
Securities Available for Sale, Gross Unrealized Gains	154,386	103,018
Securities Available for Sale, Gross Unrealized Losses	180	987
Securities Available for Sale, Estimated Fair Value	3,289,270	2,091,330
States And Political Subdivisions [Member]
Schedule Of Held-To-Maturity Securities and Available For Sale securities [Line Items]
Securities Held to Maturity, Amortized Cost	105,325	30,803
Securities Held to Maturity, Gross Unrealized Gains	6,597
Securities Held to Maturity, Gross Unrealized Losses		1,054
Securities Held to Maturity, Estimated Fair Value	111,922	29,749
Securities Available for Sale, Amortized Cost	1,996,703	2,008,618
Securities Available for Sale, Gross Unrealized Gains	158,133	53,358
Securities Available for Sale, Gross Unrealized Losses	23	21,676
Securities Available for Sale, Estimated Fair Value	2,154,813	2,040,300
Other [Member]
Schedule Of Held-To-Maturity Securities and Available For Sale securities [Line Items]
Securities Held to Maturity, Amortized Cost	1,000	1,000
Securities Held to Maturity, Gross Unrealized Losses
Securities Held to Maturity, Estimated Fair Value	1,000	1,000
Securities Available for Sale, Amortized Cost	38,001	38,809
Securities Available for Sale, Gross Unrealized Losses
Securities Available for Sale, Estimated Fair Value	$ 38,001	$ 38,809

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

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-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

- Definition

For an unclassified balance sheet, this item represents investments in debt securities which are categorized as held-to-maturity. The held-to-maturity category is for those securities that the entity has the positive intent and ability to hold until maturity.

+ References

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

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

-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

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-Subparagraph (SX 210.9-03.6)

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+ Details

- Definition

This item represents the aggregate fair value of investments in debt securities as of the balance sheet date and which are categorized as held-to-maturity.

+ References+ Details

- Definition

As of the balance sheet date, the excess of fair value over carrying value (amortized cost) of a debt security categorized as held-to-maturity, exclusive of dividend or interest income recognized but not yet received and exclusive of any write-downs for other-than-temporary impairment. Such item represents the gross unrecognized holding gain.

+ References+ Details

- Definition

As of the balance sheet date, the excess of carrying value (amortized cost) over fair value of a debt security categorized as held-to-maturity, exclusive of dividend or interest income recognized but not yet received and exclusive of any write-downs for other-than-temporary impairment. Such item represents the gross unrecognized holding loss.

+ References+ Details