Commitments And Contingencies (Environmental Remediation Contingencies) (Details) $ in Millions	Dec. 31, 2017 USD ($)
Long-term Purchase Commitment [Line Items]
Amount of environmental loss accrual expected to be recovered	$ 725
Pacific Gas And Electric Company [Member]
Long-term Purchase Commitment [Line Items]
Remediation cost recovery	90.00%
Hinkley Natural Gas Compressor Station [Member]
Long-term Purchase Commitment [Line Items]
Utility Undiscounted Future Costs	$ 145
Topock Natural Gas Compressor Station [Member]
Long-term Purchase Commitment [Line Items]
Utility Undiscounted Future Costs	289
Former Manufactured Gas Plant [Member]
Long-term Purchase Commitment [Line Items]
Utility Undiscounted Future Costs	343
Utility Owned Generation Facilities Other Than Fossil Fuel [Member]
Long-term Purchase Commitment [Line Items]
Utility Undiscounted Future Costs	145
Fossil Fuel Fired Generation [Member]
Long-term Purchase Commitment [Line Items]
Utility Undiscounted Future Costs	$ 106