Equity (Changes In Equity) (Detail) (USD $) In Millions, unless otherwise specified	1 Months Ended	3 Months Ended		6 Months Ended
	Mar. 20, 2012	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Balance at December 31, 2011				$ 12,101
Balance at December 31, 2011				12,353
Comprehensive income		247	375	493	586
Common stock issued	254			573
Share-based compensation expense				29
Common stock dividends declared				(387)
Preferred stock dividend requirement of subsidiary		(4)	(4)	(7)	(7)
Balance at June 30, 2012		12,802		12,802
Balance at June 30, 2012		13,054		13,054
Pacific Gas And Electric Company [Member]
Balance at December 31, 2011				12,384
Comprehensive income		235	368	476	578
Share-based compensation expense				1
Common stock dividends declared				(358)
Preferred stock dividend requirement		(4)	(4)	(7)	(7)
Equity contributions				565	255
Balance at June 30, 2012		$ 13,061		$ 13,061