Commitments And Contingencies (Natural Gas Supply, Transportation And Storage Commitments) (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
Sep. 30, 2012	Sep. 30, 2011
Long-term Purchase Commitment [Line Items]
2012	$ 608
2013	3,075
2014	3,405
2015	3,418
2016	3,287
Thereafter	39,341
Total	53,134
Pacific Gas And Electric Company [Member]
Long-term Purchase Commitment [Line Items]
Cost of natural gas purchases	924	1,300
Natural Gas, Gas Transportation and Gas Storage Purchases [Member]
Long-term Purchase Commitment [Line Items]
2012	254
2013	535
2014	198
2015	188
2016	153
Thereafter	974
Total	$ 2,302

Cost of natural gas purchased and associated transportation and storage costs during the period.

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- Definition

Amount of the recorded obligation to transfer funds in the future for fixed or minimum amounts or quantities of goods or services at fixed or minimum prices (for example, as in take-or-pay contracts or throughput contracts).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 440

-SubTopic 10

-Section 50

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=6394976&loc=d3e25383-109308

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 47

-Paragraph 10

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 47

-Paragraph 6

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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

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- Definition

Amount of the recorded unconditional purchase obligation maturing after the fifth fiscal year following the latest fiscal year.

+ References

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Amount of the recorded unconditional purchase obligation maturing in the fifth fiscal year following the latest fiscal year.

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Amount of the recorded unconditional purchase obligation maturing in the fourth fiscal year following the latest fiscal year.

+ References

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Amount of the recorded unconditional purchase obligation maturing in the second fiscal year following the latest fiscal year.

+ References

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Amount of the recorded unconditional purchase obligation maturing in the third fiscal year following the latest fiscal year.

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Amount of the recorded unconditional purchase obligation maturing in the next fiscal year following the latest fiscal year.

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