Fair Value Of Financial Instruments (Fair Value, Assets And Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation) (Details) (USD $) In Millions	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Fair Value Of Financial Instruments [Abstract]
Beginning balance	$ 64.0	$ 238.9	$ 45.6	$ 63.2
Included in earnings	53.8	25.1	144.9	824.9
Settlements	(50.0)	(56.4)	(102.7)	(680.5)
Transfers out of Level 3		161.8	20.0	161.8
Ending balance - September 30	67.8	45.8	67.8	45.8
Total gains for the period included in earnings attributable to the change in unrealized gains on assets still held at the reporting date	$ 53.8	$ 25.1	$ 144.9	$ 93.4

Fair Value Measurement with Unobservable Inputs Reconciliation Recurring Basis Asset and Liabilities, Change in Unrealized Gains Losses Included in Earnings on Instruments Still Held

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- Definition

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset and Liabilities, Included in Earnings

+ Details

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- Definition

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset and Liabilities, Settlements

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- Definition

Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Transfers Into Level Three

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- Definition

This element represents an asset measured at fair value using significant unobservable inputs (Level 3) which is required for reconciliation purposes of beginning and ending balances.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 157

-Paragraph 32

-Subparagraph c

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258

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