Commitments And Contingencies (Environmental Remediation Liability Disclosure) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012
Pacific Gas And Electric Company [Member]
Long-term Purchase Commitment [Line Items]
Balance at December 31, 2011	$ 785
Transfer to regulatory account for recovery	77
Amounts not recoverable in customer rates	81
Less: Payments	(22)
Balance at March 31, 2012	921
Remediation At Utility Natural Gas Compressor Site Near Hinkley, CA [Member] | Pacific Gas And Electric Company [Member]
Long-term Purchase Commitment [Line Items]
Amount of environmental loss accrual for remediation	218
Remediation At Utility Natural Gas Compressor Site Near Topock, AZ [Member]
Long-term Purchase Commitment [Line Items]
Amount of environmental loss accrual for remediation	240
Remediation At Divested Generation Facilities [Member]
Long-term Purchase Commitment [Line Items]
Amount of environmental loss accrual for remediation	80
Remediation Costs For Generation And Other Facilities And For Third-Party Disposal Sites [Member]
Long-term Purchase Commitment [Line Items]
Amount of environmental loss accrual for remediation	168
Investigation And/Or Remediation Costs At Former MGP Sites [Member]
Long-term Purchase Commitment [Line Items]
Amount of environmental loss accrual for remediation	165
Remediation Of Decommissioning Fossil Fuel-Fired Sites [Member]
Long-term Purchase Commitment [Line Items]
Amount of environmental loss accrual for remediation	$ 50