v2.3.0.11

Fair Value Disclosures (Reconciliation of Level 3 Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) (USD $) In Millions	3 Months Ended		6 Months Ended		3 Months Ended	6 Months Ended	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2010 Financial Transmission Rights [Member]	Jun. 30, 2010 Financial Transmission Rights [Member]	Jun. 30, 2011 Other Derivatives [Member]	Jun. 30, 2010 Other Derivatives [Member]	Jun. 30, 2011 Other Derivatives [Member]	Dec. 31, 2009 Other Derivatives [Member]
Beginning balance	$ (0.1)	$ 0.8	$ 0.2	$ 2.1	$ 0.9	$ 1.9	$ (0.1)	$ (0.1)	$ 0.2	$ 0.2
Total gains or (losses) (unrealized/realized) Included in regulatory assets/liabilities	(0.6)	(3.2)	(1.0)	(4.2)	(3.2)	(4.2)	(0.6)		(1.0)
Purchases	(0.5)		(1.0)				(0.5)		(1.0)
Settlements	0.4	2.6	1.0	2.3	2.3	2.3	0.4	0.3	1.0
Ending balance	(0.8)	0.2	(0.8)	0.2			(0.8)	0.2	(0.8)	0.2
Change in unrealized gains/(losses) relating to instruments still held as of June 30, 2011	$ (1.5)		$ (1.5)				$ (1.5)		$ (1.5)

X

- Definition

Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset And Liabilities Gain Loss Included In Regulatory Assets And Liabilities.

+ Details

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- Definition

Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Assets And Liabilities Change In Unrealized Gain Losses Relating To Instruments.

+ Details

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X

- Definition

Fair value measurement with unobservable inputs reconciliation recurring basis assets and liabilities value.

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X

- Definition

Purchases that have taken place during the period in relation to assets measured at fair value and categorized within Level 3 of the fair value hierarchy.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258

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- Definition

Settlements that have taken place during the period in relation to assets measured at fair value and categorized within Level 3 of the fair value hierarchy.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258

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