Cover Page Document - USD ($)	3 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2020	Feb. 10, 2021	Jun. 30, 2020
Document Period End Date		Dec. 31, 2020
ICFR Auditor Attestation Flag		true
Trading Gain (Loss)	$ 127,000,000
Entity Incorporation, State or Country Code		OR
Document Transition Report		false
Document Annual Report		true
Entity Registrant Name		PORTLAND GENERAL ELECTRIC COMPANY
Entity Central Index Key		0000784977
Document Type		10-K
Document Period End Date		Dec. 31, 2020
Entity File Number		001-05532-99
Entity Address, Address Line One		121 S.W. Salmon Street
Entity Address, City or Town		Portland
Entity Address, State or Province		OR
Entity Address, Postal Zip Code		97204
City Area Code		503
Local Phone Number		464-8000
Amendment Flag		false
Document Fiscal Year Focus		2020
Document Fiscal Period Focus		FY
Current Fiscal Year End Date		--12-31
Entity Well-known Seasoned Issuer		Yes
Entity Current Reporting Status		Yes
Entity Interactive Data Current		Yes
Entity Voluntary Filers		No
Entity Filer Category		Large Accelerated Filer
Entity Small Business		false
Entity Emerging Growth Company		false
Entity Shell Company		false
Entity Common Stock, Shares Outstanding			89,539,034
Entity Public Float				$ 3,725,882,304
Entity Tax Identification Number		93-0256820
Common Stock [Member]
Title of 12(b) Security		Common Stock, no par value
Trading Symbol		POR
Security Exchange Name		NYSE
Medium-term Notes [Member]
Title of 12(b) Security		9.31% Medium-Term Notes due 2021
Trading Symbol		POR 21
Security Exchange Name		NYSE