Cover Page - USD ($) $ / shares in Units, $ in Billions	12 Months Ended
	Dec. 31, 2020	Feb. 19, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	1-3876
Entity Registrant Name	HOLLYFRONTIER CORP
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	75-1056913
Entity Address, Address Line One	2828 N. Harwood, Suite 1300
Entity Address, City or Town	Dallas
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	75201
City Area Code	214
Local Phone Number	871-3555
Title of 12(b) Security	Common Stock $0.01 par value
Trading Symbol	HFC
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Listing, Par Value Per Share (in USD per share)	$ 0.01
Entity Public Float			$ 4.3
Entity Common Stock, Shares Outstanding (in shares)		162,414,838
Documents Incorporated by Reference	Portions of the registrant's proxy statement for its annual meeting of stockholders to be held on May 12, 2021, which proxy statement will be filed with the Securities and Exchange Commission within 120 days after December 31, 2020, are incorporated by reference in Part III.
Entity Central Index Key	0000048039
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false