Commitments and Guarantees Schdule of Long term contracts for purchase of electric power (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) MW	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Priest Rapids and Wanapum [Member]
Long-term Contract for Purchase of Electric Power [Line Items]
Revenue Bonds issued by the Public Utility Districts	$ 1,236
PGE Share of Output	8.60%
PGE Share of Capacity | MW	163
Long-term Contract for Purchase of Electric Power, Date of Contract Expiration	Jan. 01, 2052
commitment costs	$ 17	$ 16	$ 16
Wells [Member]
Long-term Contract for Purchase of Electric Power [Line Items]
Revenue Bonds issued by the Public Utility Districts	$ 757
PGE Share of Output	9.00%
PGE Share of Capacity | MW	135
Long-term Contract for Purchase of Electric Power, Date of Contract Expiration	Jan. 01, 2028
commitment costs	$ 11	$ 11	$ 10