Subsequent Events (Details) - Nothern California Wild Fire [Member] $ in Thousands	9 Months Ended
	Sep. 30, 2017 USD ($)
Subsequent Event [Line Items]
Number Of Fires	21
Number Of Acres Burned	245,000
Number Of Deaths	43
Number Of Houses Destroyed	8,900
Subsequent Event [Member]
Subsequent Event [Line Items]
Liability Insurance Coverage	$ 800,000
Number Of Fires	21
Number Of Electric Incident Reports	20
Dollar Amount Requiring Electric Incident Report	$ 50
Lower End of Range to Repair Utility Facilities	160,000
Higher End of Range to Repair Utility Facilities	$ 200,000
Number Of Acres Burned	254,000
Number Of Deaths	43
Number Of Houses Destroyed	8,900
Number Of Class Action Lawsuits	1
Estimated Maximum Capital Expenditures	$ 80,000
Estimated Minimum Capital Expenditures	60,000
Reinstated Liability Insurance	$ 550,000
Number Of Lawsuits	9