Commitments And Contingencies (Legal And Regulatory Contingencies) (Detail) (USD $)	6 Months Ended	12 Months Ended	3 Months Ended	6 Months Ended		6 Months Ended			6 Months Ended		12 Months Ended	6 Months Ended	12 Months Ended					6 Months Ended	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2012 San Bruno Explosion [Member]	Jun. 30, 2012 San Bruno Explosion [Member]	Jun. 30, 2012 San Bruno Explosion [Member] San Mateo County Superior Court [Member] Plaintiff	Jun. 30, 2012 CPUC Investigations- Maximum Penalties Per Day [Member]	Jun. 30, 2012 Tort Lawsuits [Member] San Bruno Explosion [Member] San Mateo County Superior Court [Member] LegalMatter	Jun. 30, 2012 Class Action Lawsuits [Member] San Bruno Explosion [Member] San Mateo County Superior Court [Member] LegalMatter	Jun. 30, 2012 Attorney General Unapproved [Member]	Jun. 30, 2012 PGE Corporation And Utility [Member]	Dec. 31, 2011 PGE Corporation And Utility [Member]	Jun. 30, 2012 Pacific Gas And Electric Company [Member]	Dec. 31, 2005 Pacific Gas And Electric Company [Member]	Dec. 31, 2011 Pacific Gas And Electric Company [Member]	Dec. 31, 2010 Pacific Gas And Electric Company [Member]	Dec. 31, 2009 Pacific Gas And Electric Company [Member]	Dec. 31, 2004 Pacific Gas And Electric Company [Member]	Jun. 30, 2012 Pacific Gas And Electric Company [Member] San Bruno Explosion [Member]	Jun. 30, 2012 Utility [Member]	Jun. 30, 2012 Utility [Member]	Dec. 31, 2011 Utility [Member]
Loss Contingencies [Line Items]
Accrued legal liabilities										$ 42,000,000	$ 52,000,000	$ 310,000,000		$ 277,000,000	$ 214,000,000	$ 0
Per violation penalty that may be imposed prior to the maximum statutory penalty increase	3,062					20,000
Penalty due to plat maps being misplaced		17,000,000
Number of self-reports filed with the CPUC	24
Number of gas distribution maps	16
Per violation penalty that may be imposed subsequent to the maximum statutory penalty increase						50,000
Probable penalty amount										200,000,000	200,000,000
Number of lawsuits							120	2
Number of plaintiffs					400
Cumulative charge			80,000,000	80,000,000														455,000,000
Estimated possible additional loss contingency liability																		145,000,000
Estimated maximum amount for third-party claims for San Bruno	2,998,000,000		600,000,000	600,000,000
Insurance recoveries for cost incurred related to third-party claims																			25,000,000	36,000,000	99,000,000
Utility liability insurance for damages												992,000,000
Utility liability insurance deductible												10,000,000
Amount of costs awarded by U.S. Court of Federal Claims																	92,000,000
Costs incurred to build on-site spent nuclear fuel facilities									266,000,000				205,000,000
Utility estimated cost									$ 25,000,000