Debt (Detail) (USD $)	6 Months Ended				3 Months Ended
	Jun. 30, 2012	Jun. 30, 2012 Pollution Control Bonds Series 1996 C, E, F, And 1997 B [Member]	Jun. 30, 2012 Pollution Control Bonds Series 2009 A-D [Member]	Jun. 30, 2012 Energy Recovery Bonds [Member]	Jun. 30, 2012 Floating Rate Senior Notes [Member]	Jun. 30, 2012 Minimum [Member] Pollution Control Bonds Series 1996 C, E, F, And 1997 B [Member]	Jun. 30, 2012 Minimum [Member] Pollution Control Bonds Series 2009 A-D [Member]	Jun. 30, 2012 Maximum [Member] Pollution Control Bonds Series 1996 C, E, F, And 1997 B [Member]	Jun. 30, 2012 Maximum [Member] Pollution Control Bonds Series 2009 A-D [Member]	Jun. 30, 2012 Utility [Member]	Apr. 16, 2012 Utility [Member]	Apr. 02, 2012 Utility [Member]	Jun. 30, 2012 PGE Corporation And Utility [Member]
Debt [Line Items]
Line of credit facility, maximum borrowing capacity										$ 363,000,000			$ 300,000,000
Letters of credit outstanding										3,000,000,000
Senior Notes											400,000,000
Debt instrument, interest rate						0.14%	0.13%	0.23%	0.15%		4.45%
Senior notes maturity period	2042-04-15				2012-11-20
Debt instrument, face amount		614,000,000	309,000,000		250,000,000
Repurchase of principal amount												50,000,000
Commercial paper outstanding										825,000,000
Interest rate for the Floating Rate Senior Notes					0.92%
ERB, principal outstanding				$ 223,000,000