Earnings Per Share (Reconciliation Of PG&E Corporation's Income Available For Common Shareholders And Weighted Average Common Shares Outstanding For Calculating Diluted EPS) (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income available for common shareholders	$ 576	$ 107
Weighted average common shares outstanding, basic	508	493
Employee share-based compensation	3	2
Weighted average common shares outstanding, diluted	511	495
Total earnings per common share, diluted	$ 1.13	$ 0.22