Commitments And Contingencies (Legal And Regulatory Contingencies) (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended								6 Months Ended					6 Months Ended		12 Months Ended
	Jun. 30, 2013	Jun. 30, 2013 San Bruno Explosion [Member]	Jun. 30, 2013 San Bruno Explosion [Member] San Mateo County Superior Court [Member] plaintiffs	Jun. 30, 2013 Tort Lawsuits [Member] San Bruno Explosion [Member] San Mateo County Superior Court [Member] lawsuits	Jun. 30, 2013 Class Action Lawsuits [Member] San Bruno Explosion [Member] San Mateo County Superior Court [Member] lawsuits	Jun. 30, 2013 Pipeline Safety Enhancement Plan Costs Approved, Implementation of Operational Remedies, Future Pipeline Safety Enhancement Plan Costs [Member]	Jun. 30, 2013 PGE Corporation And Utility [Member]	Dec. 31, 2012 PGE Corporation And Utility [Member]	Jun. 30, 2013 Pacific Gas And Electric Company [Member]	Dec. 31, 2012 Pacific Gas And Electric Company [Member]	Dec. 28, 2012 Pacific Gas And Electric Company [Member]	Dec. 31, 2011 Pacific Gas And Electric Company [Member]	Dec. 31, 2010 Pacific Gas And Electric Company [Member]	Jun. 30, 2013 Pacific Gas And Electric Company [Member] San Bruno Explosion [Member]	Jun. 30, 2013 Utility [Member]	Dec. 31, 2012 Utility [Member]	Jun. 30, 2013 Utility [Member] State General Fund [Member]	Jun. 30, 2013 Utility [Member] Pipeline Safety Enhancement Plan Costs Previously Disallowed By CPUC [Member]
Loss Contingencies [Line Items]
Accrued legal liabilities							$ 31	$ 34	$ 67	$ 146		$ 277	$ 214
Number of self-reports filed with the CPUC	55
Probable penalty amount							200	200
Capital Expenditures Recovery Allowed											1,000
Capital Expenditure Recovery Requested											1,400
Number of lawsuits				160	2
Number of plaintiffs			500
Number Plaintiffs Settled			150
Cumulative charge														455
Cumulative payments														388
Estimated possible additional loss contingency liability														145
Estimated maximum amount for third party claims for San Bruno		600
Utility liability insurance for damages									992
Utility liability insurance deductible									10
Cumulative insurance recoveries for cost incurred related to third-party claims															45	284
Expenses recovery allowed											165
Expenses recovery requested											751
Legal expenses									81
Number of CPUC investigative enforcement proceedings pending	3
SED recommended penalty						1,515											300	435
Total penalty recommended by various parties															2,250
City of San Bruno recommended funding for a Peninsula Emergency Response Consortium															150
City of San Bruno recommended funding for the California Pipeline Safety Trust and an independent monitor to oversee the implementation of the recommended remedial operational measures															100
TURN recommended funding to implement remedial measures and to pay for an independent monitor															50
Capitalized PSEP Costs							$ 200