Commitments And Contingencies (Nuclear Fuel Agreements) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Long-term Purchase Commitment [Line Items]
2012	$ 1,810
2013	2,860
2014	3,010
2015	3,007
2016	2,917
Thereafter	32,120
Total	45,724
Pacific Gas And Electric Company [Member]
Long-term Purchase Commitment [Line Items]
Payments for nuclear fuel	19	29
Length of contract terms, minimum (in years)	1
Length of contract terms, maximum (in years)	14
Percentage coverage of reactor requirements through 2016	100.00%
Percentage coverage of reactor requirements through 2017	100.00%
Nuclear Fuel Agreements [Member]
Long-term Purchase Commitment [Line Items]
2012	67
2013	86
2014	127
2015	193
2016	147
Thereafter	1,011
Total	$ 1,631