v2.4.0.8

Assets and Liabilities with Recurring Fair Value Measurements (Textuals) (Details) (USD $)
In Millions, unless otherwise specified

12 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]

Balance, beginning of period

$ 16

$ 17

$ 30

Included in net income:

Included in operating revenues

5

^[1]

8

^[1]

5

^[1]

Included in fuel and purchased energy expense

0

^[2]

0

^[2]

0

^[2]

Included in OCI

0

0

2

Purchases, issuances and settlements:

Purchases

6

3

0

Issuances

(2)

(1)

0

Settlements

(11)

(11)

(18)

Fair Value, Liabilities, Level 1 to Level 2 Transfers, Amount

0

0

0

Fair Value, Liabilities, Level 2 to Level 1 Transfers, Amount

0

0

0

Transfers into level 3

0

^[3],[4]

0

^[3],[4]

(2)

^[3],[4]

Transfers out of level 3

0

^[3],[5]

0

^[3],[5]

0

^[3],[5]

Balance, end of period

14

16

17

Change in unrealized gains relating to instruments still held at end of period

5

8

5

Assets and Liabilities with Recurring Fair Value Measurements (Textuals) [Abstract]

Cash Equivalents Included In Cash And Cash Equivalents, Fair Value Disclosure

889

1,274

Cash Equivalents Included In Restricted Cash, Fair Value Disclosure

$ 245

$ 228

[1]	For power contracts and other power-related products, included on our Consolidated Statements of Operations.
[2]	For natural gas contracts, swaps and options, included on our Consolidated Statements of Operations.
[3]	We transfer amounts among levels of the fair value hierarchy as of the end of each period. There were no transfers into or out of level 1 during the years ended December 31, 2013, 2012 and 2011.
[4]	There were no transfers out of level 2 into level 3 for the years ended December 31, 2013 and 2012. We had $2 million in losses transferred out of level 2 into level 3 for the year ended December 31, 2011 due to changes in market liquidity in various power and natural gas markets.
[5]	We had no significant transfers out of level 3 for the years ended December 31, 2013, 2012 and 2011.

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Fair Value, Assets Measured with Unobservable Inputs on Recurring Basis, Change in Unrealized Gain (Loss) Held At Period End

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Amount of transfers of liabilities measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2.

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Amount of transfers of liabilities measured on a recurring basis out of Level 2 of the fair value hierarchy into Level 1.

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Amount of gain (loss) recognized in other comprehensive income (loss) for financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of issuances of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of purchases of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of settlement of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of transfer of financial instrument classified as an asset into level 3 of the fair value hierarchy.

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Amount of transfers of financial instrument classified as an asset out of level 3 of the fair value hierarchy.

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