Document and Entity Information Document	Jan. 28, 2021	Dec. 02, 2020
Entity Information [Line Items]
Entity Central Index Key	0001021635
Document Type	8-K
City Area Code	405
Local Phone Number	553-3000
Entity Emerging Growth Company	false
Title of 12(b) Security		Common Stock
Written Communications	false
Document Period End Date	Jan. 28, 2021
Entity Registrant Name	OGE ENERGY CORP.
Entity Incorporation, State or Country Code	OK
Entity File Number	1-12579
Entity Tax Identification Number	73-1481638
Entity Address, Address Line One	321 North Harvey
Entity Address, Address Line Two	P.O. Box 321
Entity Address, City or Town	Oklahoma City
Entity Address, State or Province	OK
Entity Address, Postal Zip Code	73101-0321
Soliciting Material	false
Pre-commencement Tender Offer	false
Pre-commencement Issuer Tender Offer	false
Trading Symbol		OGE
Security Exchange Name		NYSE
Amendment Flag	false