Debt (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2015	Sep. 30, 2014
Debt [Line Items]
Short-term debt matured		$ (300)	$ 0
Pollution Control Bonds Series 1996 C, E, F, And 1997 B [Member]
Debt [Line Items]
Debt instrument, interest rate	0.01%	0.01%
Debt instrument, face amount	$ 614	$ 614
Pollution Control Bonds Series 2009 A-D [Member]
Debt [Line Items]
Debt instrument, interest rate	0.01%	0.01%
Debt instrument, face amount	$ 309	$ 309
Utility [Member] | Senior Notes, 3.50%, Due 2025 [Member]
Debt [Line Items]
Debt instrument, interest rate	3.50%	3.50%
Senior Notes	$ 400	$ 400
Utility [Member] | Senior Notes, 4.30%, Due 2045 [Member]
Debt [Line Items]
Debt instrument, interest rate	4.30%	4.30%
Senior Notes	$ 100	$ 100
Utility [Member] | Floating Rate Senior Notes [Member]
Debt [Line Items]
Short-term debt matured		$ (300)
PG&E Corporation [Member]
Debt [Line Items]
Line of Credit termination date	Apr. 27, 2020