Equity (Changes In Equity) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Balance at December 31, 2012			$ 13,074
Balance at December 31, 2012			13,326
Comprehensive income	165	372	769	865
Common stock issued			741
Share-based compensation expense			43
Common stock dividends declared			(609)
Preferred stock dividend requirement of subsidiary	(3)	(3)	(10)	(10)
Balance at September 30, 2013	14,260		14,260
Balance at September 30, 2013	14,008		14,008
Pacific Gas And Electric Company [Member]
Balance at December 31, 2012			13,460
Comprehensive income	166	348	741	824
Common stock issued			0
Share-based compensation expense			(1)
Common stock dividends declared			(537)
Preferred stock dividend requirement	(3)	(3)	(10)	(10)
Equity contributions			835	715
Balance at September 30, 2013	$ 14,488		$ 14,488