Fair Value Measurements with Unobservable Inputs Reconciliation Gains and Losses Recorded In Regulatory Assets Liabilities

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- Definition

This element represents total gains or losses for the period (realized and unrealized), arising from assets measured at fair value on a recurring basis using unobservable inputs (Level 3), which are included in earnings or resulted in a change in net asset value.

+ 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(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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)(1)

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

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- Definition

The increase (decrease) of assets measured at fair value on a recurring basis using unobservable inputs (Level 3) which have taken place during the period. Such increase (decrease) may be comprised of changes in fair value (gains or losses) whether realized or unrealized that have been included in earnings, changed net asset value, or other comprehensive income (a separate component of shareholders' equity); purchases, sales, issuances, or settlements of assets; and net transfers in to or out of this category within the fair value hierarchy.

+ 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(1), c(2), c(3)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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

- Definition

This element represents purchases, sales, issuances, and settlements (net) which have taken place during the period in relation to assets measured at fair value on a recurring basis using unobservable inputs (Level 3).

+ References

+ Details

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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

+ Details

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- Definition

Transfers into assets measured at fair value and categorized within Level 3 of the fair value hierarchy that have taken place during the period.

+ 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)(3)

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

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- Definition

This element represents [net] transfers in to and out of assets measured at fair value on a recurring basis using unobservable inputs (Level 3) which have taken place during the period.

+ 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(3)

-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)(3)

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

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- Definition

Transfers out of assets measured at fair value and categorized within Level 3 of the fair value hierarchy that have taken place during the period.

+ 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)(3)

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

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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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Fair Value (Details 1) (USD $) In Millions	3 Months Ended		9 Months Ended																										3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
Fair Value (Details 1) (USD $) In Millions	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011 Net Assets Vaule of Unobserable Inputs Beginning Balance [Member]	Jun. 30, 2011 Net Assets Vaule of Unobserable Inputs Beginning Balance [Member]	Sep. 30, 2010 Net Assets Vaule of Unobserable Inputs Beginning Balance [Member]	Jun. 30, 2010 Net Assets Vaule of Unobserable Inputs Beginning Balance [Member]	Sep. 30, 2011 Net Assets Vaule of Unobserable Inputs Beginning Balance [Member] Natural Gas [Member]	Jun. 30, 2011 Net Assets Vaule of Unobserable Inputs Beginning Balance [Member] Natural Gas [Member]	Sep. 30, 2010 Net Assets Vaule of Unobserable Inputs Beginning Balance [Member] Natural Gas [Member]	Jun. 30, 2010 Net Assets Vaule of Unobserable Inputs Beginning Balance [Member] Natural Gas [Member]	Sep. 30, 2011 Net Assets Vaule of Unobserable Inputs Beginning Balance [Member] Electricity [Member]	Jun. 30, 2011 Net Assets Vaule of Unobserable Inputs Beginning Balance [Member] Electricity [Member]	Sep. 30, 2010 Net Assets Vaule of Unobserable Inputs Beginning Balance [Member] Electricity [Member]	Jun. 30, 2010 Net Assets Vaule of Unobserable Inputs Beginning Balance [Member] Electricity [Member]	Sep. 30, 2011 Net Assets Vaule of Unobserable Inputs Beginning Balance [Member] Other [Member]	Jun. 30, 2011 Net Assets Vaule of Unobserable Inputs Beginning Balance [Member] Other [Member]	Sep. 30, 2010 Net Assets Vaule of Unobserable Inputs Beginning Balance [Member] Other [Member]	Jun. 30, 2010 Net Assets Vaule of Unobserable Inputs Beginning Balance [Member] Other [Member]	Sep. 30, 2011 Net Assets Value of Unobservable Inputs Ending Balance [Member]	Sep. 30, 2010 Net Assets Value of Unobservable Inputs Ending Balance [Member]	Sep. 30, 2011 Net Assets Value of Unobservable Inputs Ending Balance [Member] Natural Gas [Member]	Sep. 30, 2010 Net Assets Value of Unobservable Inputs Ending Balance [Member] Natural Gas [Member]	Sep. 30, 2011 Net Assets Value of Unobservable Inputs Ending Balance [Member] Electricity [Member]	Sep. 30, 2010 Net Assets Value of Unobservable Inputs Ending Balance [Member] Electricity [Member]	Sep. 30, 2011 Net Assets Value of Unobservable Inputs Ending Balance [Member] Other [Member]	Sep. 30, 2010 Net Assets Value of Unobservable Inputs Ending Balance [Member] Other [Member]	Sep. 30, 2011 Natural Gas [Member]	Sep. 30, 2010 Natural Gas [Member]	Sep. 30, 2011 Natural Gas [Member]	Sep. 30, 2010 Natural Gas [Member]	Sep. 30, 2011 Electricity [Member]	Sep. 30, 2010 Electricity [Member]	Sep. 30, 2011 Electricity [Member]	Sep. 30, 2010 Electricity [Member]	Sep. 30, 2011 Other [Member]	Sep. 30, 2010 Other [Member]	Sep. 30, 2011 Other [Member]	Sep. 30, 2010 Other [Member]
Fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis
Beginning Balance					$ 59	$ 65	$ 24	$ 161	$ 1	$ 1	$ 2	$ 2	$ 54	$ 57	$ 19	$ 155	$ 4	$ 7	$ 3	$ 4	$ 9	$ 133	$ 5	$ 4	$ (3)	$ 125	$ 7	$ 4
Transfers into Level 3	(7)		(4)																										(1)		0		(6)		(4)		0		0
Transfer out of Level 3	(42)		(24)																										0		1		(42)		(25)		0		0
Included in earnings	29	25	39	122																									6	3	3	4	23	21	34	117	0	1	2	1
Fair Value Measurements with Unobservable Inputs Reconciliation In Regulatory Assets Liabilities			3	4																											0	0			0	0			3	4
Purchases			1																												0				1				0
Settlements	(36)		(65)																										(1)		0		(35)		(63)		0		(2)
Purchases, issuances and settlements		(31)		(69)																										(1)		(6)		(29)		(59)		(1)		(4)
Ending balance	9		9		59	65	24	161	1	1	2	2	54	57	19	155	4	7	3	4	9	133	5	4	(3)	125	7	4
The amount of total gains (losses) included in net income attributed to the change in unrealized gains or losses related to assets still held at the end of the period	11	(1)	24	57																									6	2	5	(2)	5	(4)	17	58	0	1	2	1
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net		$ (22)		$ 52																										$ 0		$ 4		$ (22)		$ 48		$ 0		$ 0