Equity (Changes In Equity) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Balance at December 31, 2012			$ 13,074
Balance at December 31, 2012			13,326
Comprehensive income	352	247	604	493
Common stock issued			573
Share-based compensation expense			31
Common stock dividends declared			(405)
Preferred stock dividend requirement of subsidiary	(4)	(4)	(7)	(7)
Balance at June 30, 2013	14,122		14,122
Balance at June 30, 2013	13,870		13,870
Pacific Gas And Electric Company [Member]
Balance at December 31, 2012			13,460
Comprehensive income	333	235	575	476
Common stock issued			0
Share-based compensation expense			(1)
Common stock dividends declared			(358)
Preferred stock dividend requirement	(4)	(4)	(7)	(7)
Equity contributions			665	565
Balance at June 30, 2013	$ 14,334		$ 14,334