Commitments and Guarantees Schdule of Long term contracts for purchase of electric power (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014 MW	Dec. 31, 2013	Dec. 31, 2012
Priest Rapids and Wanapum [Member]
Long-term Contract for Purchase of Electric Power [Line Items]
Revenue Bonds issued by the Public Utility Districts	$ 1,102
PGE Share of Output	8.60%
PGE Share of Capacity	163
Long-term Contract for Purchase of Electric Power, Date of Contract Expiration	Dec. 31, 2052
commitment costs	14	14	14
Wells [Member]
Long-term Contract for Purchase of Electric Power [Line Items]
Revenue Bonds issued by the Public Utility Districts	215
PGE Share of Output	19.40%
PGE Share of Capacity	150
Long-term Contract for Purchase of Electric Power, Date of Contract Expiration	Dec. 31, 2018
commitment costs	10	10	10
Portland Hydro [Member]
Long-term Contract for Purchase of Electric Power [Line Items]
Revenue Bonds issued by the Public Utility Districts	4
PGE Share of Output	100.00%
PGE Share of Capacity	36
Long-term Contract for Purchase of Electric Power, Date of Contract Expiration	Dec. 31, 2017
commitment costs	$ 4	$ 4	$ 4