Fair Value Measurements (Carrying Amount And Fair Value Of Financial Instruments) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Carrying Amount [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Debt financial instrument	$ 349	$ 349
Energy recovery bonds	321	423
Carrying Amount [Member] | Pacific Gas And Electric Company [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Debt financial instrument	10,546	10,545
Fair Value Measurements, Level 2 [Member] | Fair Value [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Debt financial instrument	382	380
Energy recovery bonds	327	433
Fair Value Measurements, Level 2 [Member] | Fair Value [Member] | Pacific Gas And Electric Company [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Debt financial instrument	$ 12,412	$ 12,543