Debt (Narrative) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Debt [Line Items]
Interest including LIBOR on credit facilities		Borrowings under each credit agreement (other than swingline loans) will bear interest based on the borrower’s credit rating and on each borrower’s election of either (1) a London Interbank Offered Rate (“LIBOR”) plus an applicable margin or (2) the base rate plus an applicable margin. The base rate will equal the higher of the following: the administrative agent’s announced base rate, 0.5% above the overnight federal funds rate, and the one-month LIBOR plus an applicable margin. The borrower’s credit rating at the time of borrowing will determine the applicable rate within the following ranges. The applicable margin for LIBOR loans will range between 0.9% and 1.475% under PG&E Corporation’s credit agreement and between 0.8% and 1.275% under the Utility’s credit agreement. The applicable margin for base rate loans will range between 0% and 0.475% under PG&E Corporation’s credit agreement and between 0% and 0.275% under the Utility’s credit agreement. In addition, the facility fee under PG&E Corporation’s and the Utility’s credit agreements will range between 0.1% and 0.275% and between 0.075% and 0.225%, respectively.
Debt covenant ratio of total consolidated debt to total consolidated capitalization percentage		65.00%
Ownership requirement percentage		80.00%
Required ownership of voting capital stock		70.00%
Commercial paper, maturities (days)		365 days
Short-term debt matured		$ (500)	$ 0	$ (300)
Pacific Gas And Electric Company [Member]
Debt [Line Items]
Line of credit facility, maximum borrowing capacity	[1]	$ 3,000
Commercial paper average yield		1.11%
Line of Credit Facility, Expiration Date		Apr. 27, 2022
Short-term debt matured		$ (500)	$ 0	$ (300)
PG&E Corporation [Member]
Debt [Line Items]
Line of credit facility, maximum borrowing capacity	[2]	$ 300
Commercial paper average yield		1.29%
Line of Credit Facility, Expiration Date		Apr. 27, 2022
Credit Facilities [Member]
Debt [Line Items]
Line of credit facility, maximum borrowing capacity		$ 3,300
Commercial Paper [Member] | Pacific Gas And Electric Company [Member]
Debt [Line Items]
Average outstanding borrowings		469
Maximum outstanding balance		1,090
Commercial Paper [Member] | PG&E Corporation [Member]
Debt [Line Items]
Average outstanding borrowings		81
Maximum outstanding balance		$ 161

[1] Includes a $500 million lender commitment to the letter of credit sublimits and a $75 million commitment for swingline loans.

[2] Includes a $50 million lender commitment to the letter of credit sublimits and a $100 million commitment for swingline loans defined as loans that are made available on a same-day basis and are repayable in full within 7 days.