Subsequent Events	9 Months Ended
Sep. 30, 2020
Subsequent Events [Abstract]
Subsequent Events	Subsequent EventsOn October 28, 2020, Murphy USA Inc. issued a news release announcing an updated capital allocation strategy for the Company including a new $500 million share repurchase program to begin upon completion of the current $400 million authorization and available to be executed by December 31, 2023, and the institution of a quarterly dividend to common stockholders. The dividend of $0.25 per share, or $1.00 per share on an annualized basis, will be paid on December 1, 2020, to shareholders of record as of November 13, 2020.

The entire disclosure for significant events or transactions that occurred after the balance sheet date through the date the financial statements were issued or the date the financial statements were available to be issued. Examples include: the sale of a capital stock issue, purchase of a business, settlement of litigation, catastrophic loss, significant foreign exchange rate changes, loans to insiders or affiliates, and transactions not in the ordinary course of business.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 855
-URI http://asc.fasb.org/topic&trid=2122774

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 855
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6842918&loc=SL6314017-165662

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