Consolidated Statements Of Cash Flows (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash Flows from Financing Activities
Net issuances of commercial paper, discount	$ 5	$ 6	$ 3
Proceeds from issuance of long-term debt, net of premium, discount, and issuance costs	32	17	27
Pacific Gas And Electric Company [Member]
Cash Flows from Financing Activities
Net issuances of commercial paper, discount	5	6	3
Proceeds from issuance of long-term debt, net of premium, discount, and issuance costs	$ 32	$ 17	$ 27