Commitments And Contingencies (Legal And Regulatory Contingencies) (Details) $ in Thousands	3 Months Ended	6 Months Ended		12 Months Ended
	Jun. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)		Dec. 31, 2015 USD ($)
Loss Contingencies [Line Items]
Unrecognized Tax Benefits	$ 70,000	$ 70,000
Disputed Claims Liability Balance				$ 236,000
Charge for disallowed capital		$ 47,000	$ 425,000
Butte Fire [Member]
Loss Contingencies [Line Items]
Number of plaintiffs	2,050	2,050
Utility liability insurance for damages		$ 900,000
Number of Damaged Structures	44	44
Loss Contingency Range Of Possible Loss Minimum	$ 750,000	$ 750,000
Number of complaints filed against utility	60	60
Fire Fighting Costs Recovery Requested By Cal Fire		$ 87,000
Number Of Acres Burned	70,868	70,868
Number Of Fatalities Caused By Fire	2	2
Number Of Homes Burned By Fire	549	549
Number Of Outbuildings Burned By Fire	368	368
Number Of Commerical Properties Burned By Fire	4	4
Number Of Households Represented In Court	1,180	1,180
Number Of Master Complaints	2	2
Cumulative Legal Expenses	$ 17,000	$ 27,000
Insurance Settlements Receivable	$ 32,000	$ 32,000
Vegetation Management Contractors	2	2
Number Of Preference Households	6	6
Citation For Failing To Maintain Electric Line		$ 8,300
Office Of Emergency Services Claim		$ 190,000
Number of Citations		2
Probable Insurance Recoveries		$ 646,000
Settlement Agreements Entered By Utility		380,000
Settlement Agreement Paid By The Utility		176,000
Claim Against The Utility		85,000
Potential Safety Citations [Member]
Loss Contingencies [Line Items]
SED Maximum Statutory Penalty Per Violaiton		50
SED Administrative Limit Per Citation		8,000
Minimum [Member] | Potential Safety Citations [Member]
Loss Contingencies [Line Items]
SED fines for self-reported violations		50
Maximum [Member] | Potential Safety Citations [Member]
Loss Contingencies [Line Items]
SED fines for self-reported violations		16,800
Ex Parte Communications [Member]
Loss Contingencies [Line Items]
Payment To State General Fund		1,000
Payment To City Of San Bruno		6,000
Payment To City Of San Carlos		6,000
Revenue Requirement Reduction In Next GRC Cycle		10,000
2018 GT&S Revenue Requirement Reduction		31,750
2019 GT&S Revenue Requirement Reduction		31,750
Ex parte disallowance in 2015 GT&S rate case recognized in 2016		57,000
Ex Parte Disallowance In Twenty Fifteen GTandS Recognized In Twenty Seventeen		$ 15,000
Ex Parte Communication Count	12	12
Shareholder Derivative Lawsuits [Member]
Loss Contingencies [Line Items]
Number Of Consolidated Shareholder Derivative Lawsuits	4	4
Number Of Unconsolidated Cases In Derivative Lawsuits	3	3
Number Of Days To Make Payment From Decision	11 days
Estimated Cost Of Corporate Governance Therapeutics	$ 32,000
Maximum Amount Of Fees Paid to Plaintiffs Counsel	25,000
Maximum Amount Of Expenses Paid To Plaintiffs Counsel	500
Payment Of Individual Defendant Costs	18,300
Payment To The Corporation From Liability Insurance Carriers	90,000
Gain Contingency Unrecorded Amount	$ 65,000	$ 65,000
Number Of Years Of Corporate Governance Therapeutics	5 years
Number Of Years Of Gas Operations Therapeutics	3 years
Loss Accrual [Member] | Butte Fire [Member]
Loss Contingencies [Line Items]
Accrued Losses		0		750,000
Loss Contingency Accrual At Carrying Value	$ 574,000	574,000		690,000		$ 0
Payments For Claims		116,000		60,000	[1]
Insurance Receivable [Member] | Butte Fire [Member]
Loss Contingencies [Line Items]
Insurance Reimbursement From Contractors		75,000		50,000
Insurance Settlements Receivable	521,000	521,000		575,000		$ 0
Accrued Insurance Recoveries	$ 21,000	21,000		625,000
Cumulative Legal Expenses [Member] | Butte Fire [Member]
Loss Contingencies [Line Items]
Cumulative Legal Expenses		$ 54,000
Disallowance Of Plant Costs [Member]
Loss Contingencies [Line Items]
Percentage of Recoverable Costs Prior To Specific Date	100.00%	100.00%
Percentage of Recoverable Costs After Specific Date	25.00%	25.00%
Settlement Agreement Length	8 years
License Renewal Project Cost		$ 53,000
Recoverable Costs From Customers		18,600
Cancelled Capital Project Costs		24,000
Disallowed License Renewal Costs		23,000
Pacific Gas And Electric Company [Member]
Loss Contingencies [Line Items]
Charge for disallowed capital		47,000	$ 425,000
Utility [Member]
Loss Contingencies [Line Items]
Accrued legal liabilities	$ 43,000	$ 43,000		$ 45,000

[1] As of June 30, 2017 the Utility entered into settlement agreements in connection with the Butte fire corresponding to approximately $380 of which $176 million has been paid by the Utility.