v2.4.0.6

Derivative Instruments (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013 MMBTU MW	Dec. 31, 2012 MW MMBTU
Price Risk Derivatives [Abstract]
Power (MWh)	(16)	(16)
Natural gas (MMBtu)	162	66
Interest rate swaps	$ 1,599	$ 1,602

X

- Definition

Nonmonetary Notional Amount of Price Risk Derivatives Natural Gas

+ References

No definition available.

+ Details

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X

- Definition

Nonmonetary Notional Amount of Price Risk Derivatives Power

+ References

No definition available.

+ Details

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X

- Definition

Aggregate notional amount of interest rate derivatives, which relates to the currency amount specified in the interest rate derivative instruments.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 1A

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5579245-113959



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Notional Amount

-URI http://asc.fasb.org/extlink&oid=6519104



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 1B

-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5580258-113959

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