Murphy USA (MUSA) 10-K19 Feb 212020 FY Annual reportFinancial data

Company Profile

Cover page

Cover page - USD ($) $ in Thousands	12 Months Ended
Cover page - USD ($) $ in Thousands	Dec. 31, 2020	Jan. 31, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Document Transition Report	false
Entity File Number	001-35914
Entity Registrant Name	MURPHY USA INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	46-2279221
Entity Address, Address Line One	200 Peach Street
Entity Address, City or Town	El Dorado,
Entity Address, State or Province	AR
Entity Address, Postal Zip Code	71730-5836
City Area Code	870
Local Phone Number	875-7600
Title of 12(b) Security	Common Stock, $0.01 Par Value
Trading Symbol	MUSA
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 Company	false
Entity Emerging Growth Company	false
Entity Shell Company	false
ICFR Auditor Attestation Flag	true
Entity Public Float			$ 3,285,492
Entity Common Stock, Shares Outstanding		27,248,590
Amendment Flag	false
Entity Central Index Key	0001573516
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Documents Incorporated by Reference	Portions of the Registrant’s definitive Proxy Statement relating to the Annual Meeting of Stockholders on May 5, 2021 will be incorporated by reference in Part III herein.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 163.6	$ 280.3
Accounts receivable—trade, less allowance for doubtful accounts of $0.1 in 2020 and $1.2 in 2019	168.8	172.9
Inventories, at lower of cost or market	279.1	227.6
Prepaid expenses and other current assets	13.7	30
Total current assets	625.2	710.8
Property, plant and equipment, at cost less accumulated depreciation and amortization of $1,191.4 in 2020 and $1,079.2 in 2019	1,867.6	1,807.3
Other assets	192.9	169.1
Total assets	2,685.7	2,687.2
Current liabilities
Current maturities of long-term debt	51.2	38.8
Trade accounts payable and accrued liabilities	471.1	466.2
Income taxes payable	8.8	0
Total current liabilities	531.1	505
Long-term debt, including capitalized lease obligations	951.2	999.3
Deferred income taxes	218.4	216.7
Asset retirement obligations	35.1	32.8
Deferred credits and other liabilities	165.8	130.4
Total liabilities	1,901.6	1,884.2
Stockholders' Equity
Preferred Stock, par $0.01 (authorized 20,000,000 shares, none outstanding)	0	0
Common Stock, par $0.01, (authorized 200,000,000 shares, 46,767,164 shares issued at December 2020 and 2019, respectively)	0.5	0.5
Treasury stock (19,518,551 and 16,307,048 shares held at December 31, 2020 and 2019, respectively)	(1,490.9)	(1,099.8)
Additional paid in capital (APIC)	533.3	538.7
Retained earnings	1,743.1	1,362.9
Accumulated other comprehensive income (AOCI)	(1.9)	0.7
Total stockholders' equity	784.1	803
Total liabilities and stockholders' equity	$ 2,685.7	$ 2,687.2

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Accounts receivable - trade, allowance for doubtful accounts	$ 0.1	$ 1.2
Accumulated depreciation and amortization	$ 1,191.4	$ 1,079.2
Stockholders' Equity
Preferred stock par value (in dollars per share)		$ 0.01
Preferred stock shares authorized (in shares)	20,000,000	20,000,000
Preferred stock shares outstanding (in shares)	0	0
Common stock par value (in dollars per share)	$ 0.01	$ 0.01
Common stock shares authorized (in shares)	200,000,000	200,000,000
Common stock shares issued (in shares)	46,767,164	46,767,164
Treasury stock (in shares)	19,518,551	16,307,048

Consolidated Income Statements

Consolidated Income Statements - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Revenues
Sales and other operating revenues		$ 11,264,300	$ 14,034,600	$ 14,362,900
Operating Expenses
Station and other operating expenses		549,100	559,300	541,300
Depreciation and amortization		161,000	152,200	134,000
Selling, general and administrative		171,100	144,600	136,200
Accretion of asset retirement obligations		2,300	2,100	2,000
Acquisition related costs		1,700	0	0
Total operating expenses		10,706,600	13,766,300	14,087,100
Net settlement proceeds		0	100	50,400
Gain (loss) on sale of assets		1,300	100	(1,100)
Income from operations		559,000	268,500	325,100
Other income (expense)
Interest income		1,000	3,200	1,500
Interest expense		(51,200)	(54,900)	(52,900)
Loss on early debt extinguishment		0	(14,800)	0
Other nonoperating income (expense)		300	400	200
Total other income (expense)		(49,900)	(66,100)	(51,200)
Income before income taxes		509,100	202,400	273,900
Income tax expense (benefit)		123,000	47,600	60,300
Net Income		$ 386,100	$ 154,800	$ 213,600
Basic and Diluted Earnings Per Common Share:
Basic (in dollars per share)		$ 13.25	$ 4.90	$ 6.54
Diluted (in dollars per share)		$ 13.08	$ 4.86	$ 6.48
Weighted-average shares outstanding (in thousands):
Basic (in shares)		29,132	31,594	32,674
Diluted (in shares)		29,526	31,858	32,983
Supplemental information:
Excise taxes		$ 1,760,000	$ 1,933,300	$ 1,838,900
Petroleum product sales
Operating Revenues
Sales and other operating revenues	[1]	8,208,600	11,373,800	11,858,400
Operating Expenses
Operating expenses		7,325,700	10,707,400	11,251,100
Merchandise
Operating Revenues
Sales and other operating revenues		2,955,100	2,620,100	2,423,000
Operating Expenses
Operating expenses		2,495,700	2,200,700	2,022,500
Other operating revenues
Operating Revenues
Sales and other operating revenues		$ 100,600	$ 40,700	$ 81,500

[1]	Includes excise taxes of $1,760.0, $1,933.3 and $1.838.9 in the years ended December 31, 2020, 2019 and 2018, respectively.

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 386.1	$ 154.8	$ 213.6
Other comprehensive income (loss), net of tax
Initial fair value	0	(0.1)	0
Realized gain (loss)	(0.9)	0.2	0
Unrealized gain (loss)	(3.4)	1	0
Reclassified to interest expense	0.9	(0.2)	0
Total	(3.4)	0.9	0
Deferred income tax expense	(0.8)	0.2	0
Other comprehensive income (loss)	(2.6)	0.7	0
Comprehensive income (loss)	$ 383.5	$ 155.5	$ 213.6

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Activities
Net income	$ 386,100	$ 154,800	$ 213,600
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	161,000	152,200	134,000
Deferred and noncurrent income tax charges (benefits)	2,500	23,700	37,900
Loss on early debt extinguishment	0	14,800	0
Accretion of asset retirement obligations	2,300	2,100	2,000
Pretax (gains) losses from sale of assets	(1,300)	(100)	1,100
Net decrease (increase) in noncash operating working capital	(13,100)	(48,700)	2,300
Other operating activities - net	26,200	14,500	7,800
Net cash provided by operating activities	563,700	313,300	398,700
Investing Activities
Property additions	(230,700)	(204,800)	(204,300)
Proceeds from sale of assets	8,100	2,500	1,200
Other investing activities - net	(1,700)	(800)	(6,000)
Net cash required by investing activities	(224,300)	(203,100)	(209,100)
Financing Activities
Purchase of treasury stock	(399,600)	(165,800)	(144,400)
Dividends paid	(6,900)	0	0
Repayments of debt	(38,900)	(573,400)	(21,300)
Borrowings of debt	0	743,800	0
Early debt extinguishment costs	0	(10,400)	0
Debt issuance costs	0	(4,100)	0
Amounts related to share-based compensation	(10,700)	(4,500)	(9,400)
Net cash required by financing activities	(456,100)	(14,400)	(175,100)
Net change in cash, cash equivalents, and restricted cash	(116,700)	95,800	14,500
Cash, cash equivalents, and restricted cash at January 1	280,300	184,500	170,000
Cash, cash equivalents, and restricted cash at December 31	$ 163,600	$ 280,300	$ 184,500

Consolidated Statements of Chan

Consolidated Statements of Changes in Equity - USD ($) $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Treasury Stock	APIC	Retained Earnings	Retained EarningsCumulative Effect, Period of Adoption, Adjustment	AOCI
Balance (in shares) at Dec. 31, 2017			46,767,164
Balance at Dec. 31, 2017	$ 738.4		$ 0.5	$ (806.5)	$ 549.9	$ 994.5		$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	213.6					213.6
Purchase of treasury stock	(144.4)			(144.4)
Issuance of treasury stock	0			10.6	(10.6)
Amounts related to share-based compensation	(9.4)				(9.4)
Share-based compensation expense	9.1				9.1
Balance at Dec. 31, 2018	807.3		$ 0.5	(940.3)	539	1,208.1		0
Balance (in shares) at Dec. 31, 2018			46,767,164
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	154.8					154.8
Loss on interest rate hedge, net of tax	0.7							0.7
Purchase of treasury stock	(165.8)			(165.8)
Issuance of treasury stock	0			6.3	(6.3)
Amounts related to share-based compensation	(4.5)				(4.5)
Share-based compensation expense	10.5				10.5
Balance at Dec. 31, 2019	$ 803		$ 0.5	(1,099.8)	538.7	1,362.9		0.7
Balance (in shares) at Dec. 31, 2019	46,767,164		46,767,164
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 386.1	$ 1.1				386.1	$ 1.1
Loss on interest rate hedge, net of tax	(2.6)							(2.6)
Cash dividends declared, ($0.25 per share)	(6.9)					(6.9)
Dividend equivalent units accrued	0				0.1	(0.1)
Purchase of treasury stock	(399.6)			(399.6)
Issuance of treasury stock	(0.5)			8.5	(9)
Amounts related to share-based compensation	(10.7)				(10.7)
Share-based compensation expense	14.2				14.2
Balance at Dec. 31, 2020	$ 784.1		$ 0.5	$ (1,490.9)	$ 533.3	$ 1,743.1		$ (1.9)
Balance (in shares) at Dec. 31, 2020	46,767,164		46,767,164

Consolidated Statements of Ch_2

Consolidated Statements of Changes in Equity (Parenthetical)	12 Months Ended
	Dec. 31, 2020$ / shares
Statement of Stockholders' Equity [Abstract]
Dividends declared (in dollars per share)	$ 0.25

Description of Business and Bas

Description of Business and Basis of Presentation	12 Months Ended
Description of Business and Basis of Presentation	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business and Basis of Presentation	Description of Business and Basis of Presentation The business of Murphy USA Inc. and its subsidiaries (“Murphy USA” or the “Company”) primarily consists of the U.S. retail marketing business that was separated from its former parent company, Murphy Oil Corporation (“Murphy Oil”), plus other assets, liabilities and operating expenses of Murphy Oil that were associated with supporting the activities of the U.S. retail marketing operations. Murphy USA was incorporated in March 2013. The separation was approved by the Murphy Oil board of directors on August 7, 2013, and was completed on August 30, 2013 through the distribution of 100% of the outstanding capital stock of Murphy USA to holders of Murphy Oil common stock on the record date of August 21, 2013. Following the separation, Murphy USA is an independent, publicly traded company, and Murphy Oil retains no ownership interest in Murphy USA.

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
Significant Accounting Policies	Dec. 31, 2020
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies PRINCIPLES OF CONSOLIDATION – These consolidated financial statements were prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) and include the accounts of Murphy USA Inc. and its subsidiaries for all periods presented. All significant intercompany accounts and transactions within the consolidated financial statements have been eliminated. REVENUE RECOGNITION – Revenue is recognized when obligations under the terms of a contract with our customers are satisfied; generally, this occurs with the transfer of control of our petroleum products, convenience merchandise, Renewable Identification Numbers ("RINs") and other assets to our third-party customers. Revenue is measured as the amounts of consideration we expect to receive in exchange for transferring goods or providing services. Excise and sales tax that we collect where we have determined we are the principal in the transaction have been recorded as revenue on a jurisdiction-by-jurisdiction basis. The Company enters into buy/sell and similar arrangements when petroleum products are held at one location but are needed at a different location. The Company often pays or receives funds related to the buy/sell arrangement based on location or quality differences. The Company accounts for such transactions on a net basis in its Consolidated Income Statements. See Note 3 "Revenues" for additional information. SHIPPING AND HANDLING COSTS – Costs incurred for the shipping and handling of motor fuel are included in Petroleum product cost of goods sold in the Consolidated Income Statements. Costs incurred for the shipping and handling of convenience store merchandise are included in Merchandise cost of goods sold in the Consolidated Income Statements. TAXES COLLECTED FROM CUSTOMERS AND REMITTED TO GOVERNMENT AUTHORITIES – Excise and other taxes collected on sales of refined products and remitted to governmental agencies are included in operating revenues and operating expenses in the Consolidated Income Statements. Excise taxes on petroleum products collected and remitted were $1.8 billion in 2020, $1.9 billion in 2019, and $1.8 billion in 2018. CASH EQUIVALENTS – Short-term investments, which include government securities, money market funds and other instruments with government securities as collateral, that have a maturity of three months or less from the date of purchase are classified as cash equivalents. ACCOUNTS RECEIVABLE – The Company’s accounts receivable are recorded at the invoiced amount and do not bear interest. The accounts receivable primarily consists of amounts owed to the Company from credit card companies and by customers for wholesale sales of refined petroleum products. The allowance for doubtful accounts is the Company’s best estimate of the amount of probable credit losses on these receivables. The Company reviews this allowance for adequacy at least quarterly and bases its assessment on a combination of current information about its customers and historical write-off experience. Any trade accounts receivable balances written off are charged against the allowance for doubtful accounts. The Company has not experienced any significant credit-related losses in the past three years. INVENTORIES – Inventories of most finished products are valued at the lower of cost, generally applied on a last-in, first-out (“LIFO”) basis, or market. Any increments to LIFO inventory volumes are valued based on the first purchase price for these volumes during the year. Merchandise inventories held for resale are carried at average cost. Materials and supplies are valued at the lower of average cost or estimated value. VENDOR ALLOWANCES AND REBATES – Murphy USA receives payments for vendor allowances, volume rebates and other related payments from various suppliers of its convenience store merchandise. Vendor allowances for price markdowns are credited to merchandise cost of goods sold during the period the related markdown is recognized. Volume rebates of merchandise are recorded as reductions to merchandise cost of goods sold when the merchandise qualifying for the rebate is sold. Slotting and stocking allowances received from a vendor are recorded as a reduction to cost of sales over the period covered by the agreement. PROPERTY, PLANT AND EQUIPMENT – Additions to property, plant and equipment, including renewals and betterments, are capitalized and recorded at cost. Certain marketing facilities are primarily depreciated using the composite straight-line method with depreciable lives ranging from 16 to 25 years. Gasoline stations, improvements to gasoline stations and other assets are depreciated over 3 to 50 years by individual unit on the straight-line method. The Company capitalizes interest costs as a component of construction in progress on individually significant projects based on the weighted average interest rates incurred on its long-term borrowings. Total interest cost capitalized was $1.4 million in 2020 and 2019, respectfully and $2.2 million in 2018. The Company has undertaken like-kind exchange ("LKE") transactions under the Federal tax code in an effort to acquire and sell real and personal property in a tax efficient manner. The Company generally enters into forward transactions, in which property is sold and the proceeds are reinvested by acquiring similar property; and reverse transactions, in which property is acquired and similar property is subsequently sold. A qualified LKE intermediary is used to facilitate these LKE transactions. Proceeds from forward LKE transactions are held by the intermediary and are classified as restricted cash on the Company's balance sheet because the funds must be reinvested in similar properties. If the acquisition of suitable LKE properties is not completed within 180 days of the sale of the Company-owned property, the proceeds are distributed to the Company by the intermediary and are reclassified as available cash and applicable income taxes are determined. An exchange accommodation titleholder, a type of variable interest entity, is used to facilitate reverse like-kind exchanges. The acquired assets are held by the exchange accommodation titleholder until the exchange transactions are complete. If the Company determines that it is the primary beneficiary of the exchange accommodation titleholder, the replacements assets held by the exchange accommodation titleholder are consolidated and recorded in Property, Plant and Equipment on the Consolidated Balance Sheets. The unspent proceeds that are held in trust with the intermediary are recorded as noncurrent assets in the Consolidated Balance Sheet as the cash was restricted for the acquisition of property, plant and equipment. At December 31, 2020 and December 31, 2019, the Company had no open LKE transactions with an intermediary. IMPAIRMENT OF ASSETS – Long-lived assets, which include property and equipment and finite-lived intangible assets, are tested for recoverability whenever events or changes in circumstances indicate that the carrying amount of the asset may not be recoverable. A long-lived asset is not recoverable if its carrying amount exceeds the sum of the undiscounted cash flows expected to result from its use and eventual disposition. If a long-lived asset is not recoverable, an impairment loss is recognized for the amount by which the carrying amount of the long-lived asset exceeds its fair value, with fair value determined based on discounted estimated net cash flows or other appropriate methods. ASSET RETIREMENT OBLIGATIONS – The Company records a liability for asset retirement obligations (“ARO”) equal to the fair value of the estimated cost to retire an asset. The ARO liability is initially recorded in the period in which the obligation meets the definition of a liability, which is generally when the asset is placed in service. The ARO liability is estimated using existing regulatory requirements and anticipated future inflation rates. When the liability is initially recorded, the Company increases the carrying amount of the related long-lived asset by an amount equal to the original liability. The liability is increased over time to reflect the change in its present value, and the capitalized cost is depreciated over the useful life of the related long-lived asset. The Company reevaluates the adequacy of its recorded ARO liability at least annually. Actual costs of asset retirements such as dismantling service stations and site restoration are charged against the related liability. Any difference between costs incurred upon settlement of an asset retirement obligation and the recorded liability is recognized as a gain or loss in the Company’s Consolidated Income Statements. ENVIRONMENTAL LIABILITIES – A liability for environmental matters is established when it is probable that an environmental obligation exists and the cost can be reasonably estimated. If there is a range of reasonably estimated costs, the most likely amount will be recorded, or if no amount is most likely, the minimum of the range is used. Related expenditures are charged against the liability. Environmental remediation liabilities have not been discounted for the time value of future expected payments. Environmental expenditures that have future economic benefit are capitalized. INCOME TAXES – The Company accounts for income taxes using the asset and liability method. Under this method, income taxes are provided for amounts currently payable and for amounts deferred as tax assets and liabilities based on differences between the financial statement carrying amounts and the tax bases of existing assets and liabilities. Deferred income taxes are measured using the enacted tax rates that are assumed will be in effect when the differences reverse. The Company routinely assesses the realizability of deferred tax assets based on available positive and negative evidence including assumptions of future taxable income, tax planning strategies and other pertinent factors. A deferred tax asset valuation allowance is recorded when evidence indicates that it is more likely than not that all or a portion of these deferred tax assets will not be realized in a future period. The accounting principles for income tax uncertainties permit recognition of income tax benefits only when they are more likely than not to be realized. The Company has elected to classify any interest expense and penalties related to the underpayment of income taxes in Income tax expense in the Consolidated Income Statements. DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES – The fair value of a derivative instrument is recognized as an asset or liability in the Company’s Consolidated Balance Sheets. Upon entering into a derivative contract, the Company may designate the derivative as either a fair value hedge or a cash flow hedge, or decide that the contract is not a hedge, and therefore, recognize changes in the fair value of the contract in earnings. The Company documents the relationship between the derivative instrument designated as a hedge and the hedged items as well as its objective for risk management and strategy for use of the hedging instrument to manage the risk. Derivative instruments designated as fair value or cash flow hedges are linked to specific assets and liabilities or to specific firm commitments or forecasted transactions. The Company assesses at inception and on an ongoing basis whether a derivative instrument accounted for as a hedge is highly effective in offsetting changes in the fair value or cash flows of the hedged item. A derivative that is not a highly effective hedge does not qualify for hedge accounting. The change in the fair value of a qualifying fair value hedge is recorded in earnings along with the gain or loss on the hedged item. The effective portion of the change in the fair value of a qualifying cash flow hedge is recorded in Accumulated other comprehensive income (AOCI) in the consolidated Balance Sheets until the hedged item is recognized currently in earnings. If a derivative instrument no longer qualifies as a cash flow hedge and the underlying forecasted transaction is no longer probable of occurring, hedge accounting is discontinued and the gain or loss recorded in Accumulated other comprehensive income is recognized immediately in earnings. See Note 12 "Financial Instruments and Risk Management" and Note 15 "Assets and Liabilities Measured at Fair Value" for further information about the Company’s derivatives. STOCK-BASED COMPENSATION – The fair value of awarded stock options, restricted stock, restricted stock units and performance stock units is determined based on a combination of management assumptions for awards issued. The Company uses the Black-Scholes option pricing model for computing the fair value of stock options. The primary assumptions made by management included the expected life of the stock option award and the expected volatility of the Company’s common stock prices. The Company uses both historical data and current information to support its assumptions. Stock option expense is recognized on a straight-line basis over the requisite service period of three years. The Company uses a Monte Carlo valuation model to determine the fair value of performance-based stock units that are based on performance compared against a peer group and the related expense is recognized over the three-year requisite service period. Management estimates the number of all awards that will not vest and adjusts its compensation expense accordingly. Differences between estimated and actual vested amounts are accounted for as an adjustment to expense when known. See Note 10 "Incentive Plans" or a discussion of the basis of allocation of such costs. USE OF ESTIMATES – In preparing the financial statements of the Company in conformity with U.S. GAAP, management has made a number of estimates and assumptions related to the reporting of assets, liabilities, revenues, and expenses and the disclosure of contingent assets and liabilities. Actual results may differ from the

Revenues

Revenues	12 Months Ended
Revenues	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Revenues	Revenues Revenue Recognition The following table disaggregates our revenue by major source for the years ended December 31, 2020, 2019, and 2018. Years Ended December 31, (Millions of dollars) 2020 2019 2018 Marketing Segment Petroleum product sales (at retail) 1 $ 7,444.6 $ 10,184.0 $ 10,459.2 Petroleum product sales (at wholesale) 1 764.0 1,189.8 1,399.2 Total petroleum product sales 8,208.6 11,373.8 11,858.4 Merchandise sales 2,955.1 2,620.1 2,423.0 Other operating revenues: RINs 95.5 34.8 75.2 Other revenues 2 4.8 5.6 5.7 Total marketing segment revenues 11,264.0 14,034.3 $ 14,362.3 Corporate and Other Assets 0.3 0.3 $ 0.6 Total revenues $ 11,264.3 $ 14,034.6 $ 14,362.9 1 Includes excise and sales taxes that remain eligible for inclusion under Topic 606 2 Primarily includes collection allowance on excise and sales taxes and other miscellaneous items Marketing segment Petroleum product sales (at retail). For our retail store locations, the revenue related to petroleum product sales is recognized as the fuel is pumped to our customers. The transaction price at the pump typically includes some portion of sales or excise taxes as levied in the respective jurisdictions. Those taxes that are collected for remittance to governmental entities on a pass through basis are not recognized as revenue and they are recorded to a liability account until they are paid. Our customers typically use a mixture of cash, checks, credit cards and debit cards to pay for our products as they are received. We have accounts receivable from the various credit/debit card providers at any point in time related to product sales made on credit cards and debit cards. These receivables are typically collected in two Petroleum product sales (at wholesale). Our sales of petroleum products at wholesale are generally recorded as revenue when the deliveries have occurred and legal ownership of the product has transferred to the customer. Title transfer for bulk refined product sales typically occurs at pipeline custody points and upon trucks loading at product terminals. For bulk pipeline sales, we record receivables from customers that are generally collected within a week from custody transfer date. For our rack product sales, the majority of our customers' accounts are drafted by us within 10 days from product transfer. Merchandise sales. For our retail store locations, the revenue related to merchandise sales is recognized as the customer completes their purchase at our locations. The transaction price typically includes some portion of sales tax as levied in the respective jurisdictions. Those taxes that are collected for remittance to governmental entities on a pass through basis are not recognized as revenue and they are recorded to a liability account until they are paid. As noted above, a mixture of payment types are used for these revenues and the same terms for credit/debit card receivables are realized. The most significant judgment with respect to merchandise sales revenue is determining whether we are the principal or agent for some categories of merchandise such as lottery tickets, lotto tickets, newspapers and other small categories of merchandise. For scratch-off lottery tickets, we have determined we are the principal in the majority of the jurisdictions and therefore we record those sales on a gross basis. We have some categories of merchandise (such as lotto tickets) where we are the agent and the revenues recorded for those transactions are our net commission only. In June 2018 the Company initiated a loyalty pilot program through a limited number of its retail locations and was rolled out chain-wide in March 2019. The customers earn rewards based on their spending or other promotional activities. This program creates a performance obligation which requires us to defer a portion of sales revenue to the loyalty program participants until they redeem their rewards. The rewards may be redeemed for free or discounted merchandise or cash discounts on fuel purchases. Earned rewards expire after an account is inactive for a period of 90 days. We recognize loyalty revenue when a customer redeems an earned reward. Deferred revenue associated with Murphy Rewards is included in Trade accounts payable and accrued liabilities in our Consolidated Balance Sheet. The deferred revenues recorded in 2020 and 2019 were immaterial. RINs sales. For the sale of RINs, we recognize revenue when the RIN is transferred to the counter-party and the sale is completed. Receivables from our counter-parties related to the RIN sales are typically collected within five days of the sale. Other revenues. Items reported as other operating revenues include collection allowances for excise and sales tax and other miscellaneous items and are recognized as revenue when the transaction is completed. Accounts receivable

Inventories

Inventories	12 Months Ended
Inventories	Dec. 31, 2020
Inventory Disclosure [Abstract]
Inventories	Inventories Inventories consisted of the following: December 31, (Millions of dollars) 2020 2019 Finished products - FIFO basis $ 223.0 $ 259.2 Less LIFO reserve - finished products (101.3) (160.8) Finished products - LIFO basis 121.7 98.4 Store merchandise for resale 152.0 123.0 Materials and supplies 5.4 6.2 Total inventories $ 279.1 $ 227.6

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
Property, Plant and Equipment	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Property, Plant and Equipment December 31, 2020 December 31, 2019 (Millions of dollars) Estimated Useful Life Cost Net Cost Net Land $ 609.5 $ 609.5 $ 598.6 $ 598.6 Pipeline and terminal facilities 16 to 25 years 79.8 43.5 77.5 43.7 Retail gasoline stations 3 to 50 years 2,179.7 1,123.2 2,034.4 1,073.6 Buildings 20 to 45 years 66.7 48.5 60.5 44.9 Other 3 to 20 years 123.3 42.9 115.5 46.5 $ 3,059.0 $ 1,867.6 $ 2,886.5 $ 1,807.3 Depreciation expense of $160.0 million, $151.2 million and $132.5 million was recorded for the years ended December 31, 2020, 2019 and 2018, respectively.

Accounts Payable and Accrued Li

Accounts Payable and Accrued Liabilities	12 Months Ended
Accounts Payable and Accrued Liabilities	Dec. 31, 2020
Payables and Accruals [Abstract]
Accounts Payable and Accrued Liabilities	Accounts Payable and Accrued Liabilities Trade accounts payable and accrued liabilities consisted of the following: December 31, (Millions of dollars) 2020 2019 Trade accounts payable $ 261.0 $ 280.8 Excise taxes/withholdings payable 84.1 86.2 Accrued insurance obligations 30.3 24.4 Accrued taxes other than income 31.7 25.6 Accrued compensation and benefits 32.5 26.5 Other 31.5 22.7 Accounts payable and accrued liabilities $ 471.1 $ 466.2

Long-Term Debt

Long-Term Debt	12 Months Ended
Long-Term Debt	Dec. 31, 2020
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt Long-term debt consisted of the following: December 31, (Millions of dollars) 2020 2019 5.625% senior notes due 2027 (net of unamortized discount of $2.4 at 2020 and $2.7 at 2019) 297.6 297.3 4.75% senior notes due 2029 (net of unamortized discount of $5.4 at 2020 and $6.1 at 2019) 494.6 493.9 Term loan due 2023 (effective interest rate of 2.67% at 2020 and 4.31% at 2019) 212.5 250.0 Capitalized lease obligations, vehicles, due through 2024 2.1 2.4 Unamortized debt issuance costs (4.4) (5.5) Total long-term debt 1,002.4 1,038.1 Less current maturities 51.2 38.8 Total long-term debt, net of current $ 951.2 $ 999.3 Senior Notes On April 25, 2017, Murphy Oil USA, Inc., our primary operating subsidiary, issued $300 million of 5.625% Senior Notes due 2027 (the "2027 Senior Notes") under its existing shelf registration statement. The 2027 Senior Notes are fully and unconditionally guaranteed by Murphy USA, and are guaranteed by certain 100% owned subsidiaries that guarantee our credit facilities. The indenture governing the 2027 Senior Notes contains restrictive covenants that limit, among other things, the ability of Murphy USA, Murphy Oil USA, Inc. and the restricted subsidiaries to incur additional indebtedness or liens, dispose of assets, make certain restricted payments or investments, enter into transactions with affiliates or merge with or into other entities. On September 13, 2019, Murphy Oil USA, Inc., issued $500 million of 4.75% Senior Notes due 2029 (the “2029 Senior Notes”). The net proceeds from the issuance of the 2029 Senior Notes were used to fund, in part, the tender offer and redemption of the prior notes issuance. The 2029 Senior Notes are fully and unconditionally guaranteed by Murphy USA, and are guaranteed by certain 100% owned subsidiaries that guarantee our credit facilities. The indenture governing the 2029 Senior Notes contains restrictive covenants that are essentially identical to the covenants for the 2027 Senior Notes. The 2027 and 2029 Senior Notes and the guarantees rank equally with all of our and the guarantors’ existing and future senior unsecured indebtedness and effectively junior to our and the guarantors’ existing and future secured indebtedness (including indebtedness with respect to the credit facilities) to the extent of the value of the assets securing such indebtedness. The 2027 and 2029 Senior Notes are structurally subordinated to all of the existing and future third-party liabilities, including trade payables, of our existing and future subsidiaries that do not guarantee the notes. See Note 21 "Subsequent Events" for additional information regarding a new issuance of senior notes. Credit Facilities and Term Loan In August 2019, we amended and extended our existing credit agreement. The effective date of the agreement was extended to August, 2024. The credit agreement provides for a committed $325 million asset-based loan (ABL) facility (with availability subject to the borrowing base described below) and a $200 million term loan facility with an additional $50 million available until December 31, 2019. It also provides for a $150 million uncommitted incremental facility. On August 27, 2019, Murphy Oil USA, Inc. borrowed $200 million under the term loan facility that has a four-year term and prepaid the remaining balance of the prior term loan of $57 million. On December 31, 2019, we borrowed the additional $50 million term loan, and at December 31, 2020 had an outstanding balance of $212.5 million. The term loan is due August 2023 and requires quarterly principal payments of $12.5 million beginning April 1, 2020. As of December 31, 2020, we had zero outstanding under our ABL facility. The borrowing base is expected, at any time of determination, to be an amount (net of reserves) equal to the sum of: • 100% of eligible cash at such time, plus • 90% of eligible credit card receivables at such time, plus • 90% of eligible investment grade accounts, plus • 85% of eligible other accounts, plus • 80% of eligible product supply/wholesale refined products inventory at such time, plus • 75% of eligible retail refined products inventory at such time, plus the lesser of (i) 70% of the average cost of eligible retail merchandise inventory at such time and (ii) 85% of the net orderly liquidation value of eligible retail merchandise inventory at such time. The ABL facility includes a $100 million sublimit for the issuance of letters of credit. Letters of credit issued under the ABL facility reduce availability under the ABL facility. Interest payable on the credit facilities is based on either: • the London interbank offered rate, adjusted for statutory reserve requirements (the “Adjusted LIBO Rate”); or • the Alternate Base Rate, which is defined as the highest of (a) the prime rate, (b) the federal funds effective rate from time to time plus 0.50% per annum and (c) the one-month Adjusted LIBO Rate plus 1.00% per annum, plus, (A) in the case Adjusted LIBO Rate borrowings, (i) with respect to the ABL facility, spreads ranging from 1.50% to 2.00% per annum depending on a total debt to EBITDA ratio under the ABL facility or (ii) with respect to the term facility, spreads ranging from 2.50% to 2.75% per annum depending on a total debt to EBITDA ratio and (B) in the case of Alternate Base Rate borrowings, (i) with respect to the ABL facility, spreads ranging from 0.50% to 1.00% per annum depending on a total debt to EBITDA ratio under the ABL facility or (ii) with respect to the term facility, spreads ranging from 1.50% to 1.75% per annum depending on a total debt to EBITDA ratio. The interest rate period with respect to the Adjusted LIBO Rate interest rate option can be set at one-, two-, three-, or six-months as selected by us in accordance with the terms of the credit agreement. The credit agreement contains certain covenants that limit, among other things, the ability of us and our subsidiaries to incur additional indebtedness or liens, to make certain investments, to enter into sale-leaseback transactions, to make certain restricted payments, to enter into consolidations, mergers or sales of material assets and other fundamental changes, to transact with affiliates, to enter into agreements restricting the ability of subsidiaries to incur liens or pay dividends, or to make certain accounting changes. In addition, the credit agreement requires us to maintain a minimum fixed charge coverage ratio of a minimum of 1.0 to 1.0 when availability for at least three The credit agreement contains restrictions on certain payments, including dividends, when availability under the credit agreement is less than or equal to the greater of $100 million and 25% of the lesser of the revolving commitments and the borrowing base and our fixed charge coverage ratio is less than 1.0 to 1.0 (unless availability under the credit agreement is greater than $100 million and 40% of the lesser of the revolving commitments and the borrowing base). As of December 31, 2020, our ability to make restricted payments was not limited as our availability under the borrowing base was more than $100 million, while our fixed charge coverage ratio under our credit agreement was less than 1.0 to 1.0. As of December 31, 2020, the Company had a shortfall of approximately $82.7 million of our net income and retained earnings subject to such restrictions before the fixed charge coverage ratio would exceed 1.0 to 1.0. All obligations under the credit agreement are guaranteed by Murphy USA and the subsidiary guarantors party thereto, and all obligations under the credit agreement, including the guarantees of those obligations, are secured by certain assets of Murphy USA, Murphy Oil USA, Inc. and the guarantors party thereto. See also Note 21 "Subsequent Events" for additional information concerning changes to our credit facilities and term loan.

Asset Retirement Obligations (A

Asset Retirement Obligations (ARO)	12 Months Ended
Asset Retirement Obligations (ARO)	Dec. 31, 2020
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligations (ARO)	Asset Retirement Obligations (ARO) The majority of the ARO recognized by the Company at December 31, 2020 and 2019 related to the estimated costs to dismantle and abandon certain of its retail gasoline stations. The Company has not recorded an ARO for certain of its marketing assets because sufficient information is presently not available to estimate a range of potential settlement dates for the obligation. These assets are consistently being upgraded and are expected to be operational into the foreseeable future. In these cases, the obligation will be initially recognized in the period in which sufficient information exists to estimate the obligation. A reconciliation of the beginning and ending aggregate carrying amount of the ARO is shown in the following table. December 31, (Millions of dollars) 2020 2019 Balance at beginning of period $ 32.8 $ 30.7 Accretion expense 2.3 2.1 Settlement of liabilities (0.8) (0.4) Liabilities incurred 0.8 0.4 Balance at end of period $ 35.1 $ 32.8

Income Taxes

Income Taxes	12 Months Ended
Income Taxes	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The components of income before income taxes for each of the three years ended December 31, 2020 and income tax expense (benefit) attributable thereto were as follows: Years Ended December 31, (Millions of dollars) 2020 2019 2018 Income (loss) before income taxes $ 509.1 $ 202.4 $ 273.9 Income tax expense (benefit) Federal - Current $ 96.0 15.6 18.4 Federal - Deferred 4.7 21.7 31.0 State - Current and deferred 22.3 10.3 10.9 Total $ 123.0 $ 47.6 $ 60.3 The following table reconciles income taxes based on the U.S. statutory tax rate to the Company’s income tax expense (benefit). Years Ended December 31, (Millions of dollars) 2020 2019 2018 Income tax expense based on the U.S. statutory tax rate $ 106.9 $ 42.5 $ 57.5 State income taxes, net of federal benefit 17.5 8.6 8.3 Federal credits (1.9) (2.3) (2.0) Other, net 0.5 (1.2) (3.5) Total $ 123.0 $ 47.6 $ 60.3 An analysis of the Company’s deferred tax assets and deferred tax liabilities at December 31, 2020 and 2019 showing the tax effects of significant temporary differences is as follows: December 31, (Millions of dollars) 2020 2019 Deferred tax assets Property costs and asset retirement obligations $ 4.5 $ 3.7 Employee benefits 8.0 6.1 Operating leases liability 31.6 25.0 Other deferred tax assets 7.2 2.1 Total gross deferred tax assets 51.3 36.9 Deferred tax liabilities Accumulated depreciation and amortization (213.2) (191.2) State deferred taxes (20.2) (27.9) Operating leases right of use assets (31.0) (24.8) Other deferred tax liabilities (5.3) (9.7) Total gross deferred tax liabilities (269.7) (253.6) Net deferred tax liabilities $ (218.4) $ (216.7) In management’s judgment, the net deferred tax assets in the preceding table will more likely than not be realized as reductions of future taxable income or by utilizing available tax planning strategies. As of December 31, 2020, the earliest year remaining open for Federal and state audit and/or settlement is 2017 and 2015, respectively. Although the Company believes that recorded liabilities for unsettled issues are adequate, additional gains or losses could occur in future periods from resolution of outstanding unsettled matters. The FASB’s rules for accounting for income tax uncertainties clarify the criteria for recognizing uncertain income tax benefits and require additional disclosures about uncertain tax positions. Under U.S. GAAP the financial statement recognition of the benefit for a tax position is dependent upon the benefit being more likely than not to be sustainable upon audit by the applicable taxing authority. If this threshold is met, the tax benefit is then measured and recognized at the largest amount that is greater than 50 percent likely of being realized upon ultimate settlement. Liabilities associated with uncertain income tax positions are included in Deferred Credits and Other Liabilities in the Consolidated Balance Sheets. A reconciliation of the beginning and ending amount of the consolidated liability for unrecognized income tax benefits during the year ended December 31, 2020 and 2019 is shown in the following table. Year Ended December 31, (Millions of dollars) 2020 2019 Balance at January 1 $ 0.6 $ 0.7 Additions for tax positions related to prior years 0.1 0.5 Settlements with taxing authorities (0.3) (0.6) Balance at December 31 $ 0.4 $ 0.6 All additions or reductions to the above liability affect the Company’s effective tax rate in the respective period of change. The Company accounts for any applicable interest and penalties on uncertain tax positions as a component of income tax expense. Income tax expense for the years ended December 31, 2020, 2019 and 2018 included immaterial amounts of interest and penalties, associated with uncertain tax positions. Of these amounts shown in the table, $0.3 million and $0.5 million represent the amount of unrecognized tax benefits that, if recognized, would impact our effective tax rate. During the next twelve months, the Company does not expect a material change to the liability for uncertain taxes. Although existing liabilities could be reduced by settlement with taxing authorities or lapse due to statute of limitations, the Company believes that the changes in its unrecognized tax benefits due to these events will not have a material impact on the Consolidated Income Statement during 2021.

Incentive Plans

Incentive Plans	12 Months Ended
Incentive Plans	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Incentive Plans	Incentive Plans 2013 Long-Term Incentive Plan Effective August 30, 2013, certain of our employees began to participate in the Murphy USA 2013 Long-Term Incentive Plan, which was subsequently amended and restated effective as of February 8, 2017 (the “MUSA 2013 Plan”). The MUSA 2013 Plan authorizes the Executive Compensation Committee of our Board of Directors (“the Committee”) to grant non-qualified or incentive stock options, stock appreciation rights, stock awards (including restricted stock and restricted stock unit awards), dividend equivalent units, cash awards, and performance awards to our employees. No more than 5.5 million shares of common stock may be delivered under the MUSA 2013 Plan and no more than 1 million shares of common stock may be awarded to any one employee, subject to adjustment for changes in capitalization. The maximum cash amount payable pursuant to any “performance-based” award to any participant in any calendar year is $5.0 million. During the period from August 30, 2013 to December 31, 2020, the Company granted a total of 2,491,559 awards from the MUSA 2013 Plan which leaves 3,008,441 remaining shares to be granted in future years (after consideration of the amendments made to the MUSA 2013 Plan in February 2014 by the Board of Directors). At present, the Company expects to issue all shares that vest out of existing treasury shares rather than issuing new common shares. 2013 Stock Plan for Non-employee Directors Effective August 8, 2013, Murphy USA adopted the 2013 Murphy USA Stock Plan for Non-employee Directors (the “Directors Plan”). The directors for Murphy USA are compensated with a mixture of cash payments and equity- based awards. Awards under the Directors Plan may be in the form of restricted stock, restricted stock units, stock options, or a combination thereof. An aggregate of 500,000 shares of common stock shall be available for issuance of grants under the Directors Plan. Since 2013, 133,430 time-based restricted stock units have been granted under the terms of the Directors Plan which leaves 366,570 shares available to be granted in the future. Amounts recognized in the financial statements by the Company with respect to all share-based plans are shown in the following table. Years Ended December 31, (Millions of dollars) 2020 2019 2018 Compensation charged against income before income tax benefit $ 14.3 $ 10.5 $ 9.2 Related income tax benefit recognized in income $ 3.0 $ 2.2 $ 1.9 As of December 31, 2020, there was $18.1 million in compensation costs to be expensed over approximately the next 1.7 years related to unvested share-based compensation arrangements granted by the Company. Employees who have stock options are required to net settle their options in shares, after applicable statutory withholding taxes are considered, upon each stock option exercise. Therefore, no cash is received upon exercise. Total income tax benefits realized from tax deductions related to stock option exercises under share-based payment arrangements were $0.7 million, $0.1 million, and $2.1 million for the years ended December 31, 2020, 2019, and 2018, respectively. Concurrent with its initial quarterly dividend in December 2020, the Company issued dividend equivalent units ("DEU") on all outstanding, unvested equity awards (except stock options) in an amount commensurate with regular quarterly dividends paid on common stock. The terms of the DEU mirror the underlying awards and will only vest if the related award vests. DEU's issued are included with grants in each respective table as applicable. STOCK OPTIONS – The Committee fixes the option price of each option granted at no less than fair market value (FMV) on the date of the grant and fixes the option term at no more than 7 years from such date. In February 2020, the Committee granted nonqualified stock options to certain employees of the Company. Following are the assumptions used by the Company to value the original awards: Years Ended December 31, 2020 2019 2018 Fair value per option grant $ 28.28 $ 20.48 $ 17.32 Assumptions Dividend yield — — — Expected volatility 28.1 % 26.8 % 27.0 % Risk-free interest rate 1.5 % 2.5 % 2.4 % Expected life (years) 4.7 4.5 3.9 Stock price at valuation date $ 106.72 $ 76.15 $ 71.00 Changes in options outstanding for Company employees during the period from December 31, 2019 to December 31, 2020 are presented in the following table: Options Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (Millions of Dollars) Outstanding at December 31, 2019 392,300 68.52 Granted 79,200 105.57 Exercised (148,800) 64.21 Outstanding at December 31, 2020 322,700 $ 79.60 4.6 $ 16.5 Exercisable at December 31, 2020 110,700 $ 66.91 3.3 $ 7.1 Additional information about stock options outstanding at December 31, 2020 is shown below: Options Outstanding Options Exercisable Range of Exercise Prices per Option No. of Options Avg. Life Remaining in Years No. of Options Avg. Life Remaining in Years $50.00 to $59.99 7,300 2.1 7,300 2.1 $60.00 to $69.99 69,500 3.1 69,500 3.1 $70.00 to $79.99 166,700 4.6 33,900 3.9 $80.00 to $89.99 3,600 6.2 — $100.00 to $109.99 75,600 6.1 — 322,700 4.6 110,700 3.3 RESTRICTED STOCK UNITS (MUSA 2013 Plan) – The Committee has granted time based restricted stock units (RSUs) as part of the compensation plan for its executives and certain other employees since its inception. The awards granted in the current year were under the MUSA 2013 Plan, are valued at the grant date fair value, and vest over three years. Changes in restricted stock units outstanding for Company employees during the period from December 31, 2019 to December 31, 2020 are presented in the following table: Employee RSUs Number of units Weighted Average Grant Date Fair Value Total Fair Value (Millions of Dollars) Outstanding at December 31, 2019 198,915 $ 70.58 Granted 55,734 $ 90.09 Vested and issued (59,324) $ 66.31 $ 6.4 Forfeited (12,530) $ 78.43 Outstanding at December 31, 2020 182,795 $ 77.38 $ 23.9 PERFORMANCE-BASED RESTRICTED STOCK UNITS (MUSA 2013 Plan) – In February 2020, the Committee awarded performance-based restricted stock units (performance units) to certain employees. Half of the performance units vest based on a three-year return on average capital employed (ROACE) calculation and the other half vest based on a three-year total shareholder return (TSR) calculation that compares MUSA to a group of 18 peer companies. The portion of the awards that vest based on TSR qualify as a market condition and must be valued using a Monte Carlo valuation model. For the TSR portion of the awards, the fair value was determined to be $142.07 per unit. For the ROACE portion of the awards, the valuation was based on the grant date fair value of $106.72 per unit and the number of awards will be periodically assessed to determine the probability of vesting. Changes in performance-based restricted stock units outstanding for Company employees during the period from December 31, 2019 to December 31, 2020 are presented in the following table: Employee PSU's Number of Units Weighted Average Grant Date Fair Value Total Fair Value (Millions of Dollars) Outstanding at December 31, 2019 131,200 $ 82.98 Granted 64,290 $ 122.95 Vested and issued (65,745) $ 85.04 $ 7.0 Forfeited (405) $ 65.75 Outstanding at December 31, 2020 129,340 $ 97.01 $ 16.9 RESTRICTED STOCK UNITS (Directors Plan) – The Committee has also granted time based RSUs to the non-employee directors of the Company as part of their overall compensation package for being a member of the Board of Directors. These awards typically vest at the end of three years. Changes in restricted stock units outstanding for Company non-employee directors during the period from December 31, 2019 to December 31, 2020 are presented in the following table: Director RSU's Number of Units Weighted Average Grant Date Fair Value Total Fair Value (Millions of Dollars) Outstanding at December 31, 2019 33,607 $ 70.68 Granted 9,801 $ 105.33 Vested and issued (12,404) $ 66.01 $ 1.3 Outstanding at December 31, 2020 31,004 $ 83.31 $ 4.1

Employee and Retiree Benefit Pl

Employee and Retiree Benefit Plans	12 Months Ended
Employee and Retiree Benefit Plans	Dec. 31, 2020
Retirement Benefits [Abstract]
Employee and Retiree Benefit Plans	Employee and Retiree Benefit Plans THRIFT PLAN – Most full-time employees of the Company may participate in defined contribution savings plans by contributing up to a specified percentage of their base pay. The Company matches contributions at 100% of each employee’s contribution with a maximum match of 6%. In addition, the Company makes profit sharing contributions on an annual basis. Eligible employees receive a stated percentage of their base and incentive pay of 5%, 7%, or 9% determined on a formula that is based on a combination of age and years of service. The Company’s combined expenses related to this plan were $15.3 million in 2020, $12.9 million in 2019 and $9.7 million in 2018. PROFIT SHARING PLAN – Eligible part-time employees may participate in the Company’s noncontributory profit sharing plan. Each year, the Company may make a discretionary employer contribution in an amount determined and authorized at the discretion of the Board of Directors. Eligible employees receive an allocation based on their compensation earned for the year the contribution is allocated. The Company’s expenses related to this plan were $1.8 million in 2020, $1.5 million in 2019 and $(0.8) million in 2018.

Financial Instruments and Risk

Financial Instruments and Risk Management	12 Months Ended
Financial Instruments and Risk Management	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Financial Instruments and Risk Management	Financial Instruments and Risk Management DERIVATIVE INSTRUMENTS — The Company makes limited use of derivative instruments to manage certain risks related to commodity prices and interest rates. The use of derivative instruments for risk management is covered by operating policies and is closely monitored by the Company’s senior management. The Company does not hold any derivatives for speculative purposes and it does not use derivatives with leveraged or complex features. Derivative instruments are traded primarily with creditworthy major financial institutions or over national exchanges such as the New York Mercantile Exchange (“NYMEX”). For accounting purposes, the Company has not designated commodity derivative contracts as hedges, and therefore, it recognizes all gains and losses on these derivative contracts in its Consolidated Statement of Income. Certain interest rate derivative contracts were accounted for as hedges and gain or loss associated with recording the fair value of these contracts was deferred in AOCI until the anticipated transactions occur. As of December 31, 2020, all current commodity derivative activity is immaterial. At December 31, 2020 and 2019, cash deposits of $0.6 million and $1.0 million, respectively, related to commodity derivative contracts were reported in Prepaid expenses and other current assets in the Consolidated Balance Sheets. These cash deposits have not been used to reduce the reported net liabilities on the derivative contracts at December 31, 2020 and 2019. Interest Rate Risks

Earnings Per Share

Earnings Per Share	12 Months Ended
Earnings Per Share	Dec. 31, 2020
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share Basic earnings per common share is computed by dividing net income available to common stockholders by the weighted average of common shares outstanding during the period. Diluted earnings per common share adjusts basic earnings per common share for the effects of stock options and restricted stock in the periods where such items are dilutive. On July 24, 2019, the Board of Directors approved an up to $400 million share repurchase program to be executed over the two-year period ending July 2021, which was completed in November 2020. On October 28, 2020, a new authorization of $500 million was put into place through December 2023. During 2020, the total repurchases were 3,338,028 common shares for $399.6 million,or $119.70 per share. The number repurchased in 2020 under the July 2019 authorization were 2,368,374 common shares for $274.6 million, or $115.93 per share and shares purchased under the October 2020 authorization were 969,654 common shares for $125.0 million, or $128.91 per share, leaving approximately $375.0 million, at December 31, 2020, available until December 2023. During 2019, the total number of common shares repurchased were 1,898,023 for $165.8 million, or $87.35 per share, of which 1,393,626 common shares were under the July 2019 plan for $125.0 million, or $89.70 per share and other shares purchased were 504,397 common shares for $40.8 million, or $80.85 per share. During 2018 the Company acquired 1,994,632 common shares at an average price of $72.39. The following table provides a reconciliation of basic and diluted earnings per share computations for the years ended December 31, 2020, 2019 and 2018 (in millions, except per share amounts): Years ended December 31, (Millions of dollars except per share amounts) 2020 2019 2018 Earnings per common share: Net income per share - basic Net income attributable to common stockholders $ 386.1 $ 154.8 $ 213.6 Weighted average common shares outstanding (in thousands) 29,132 31,594 32,674 Earnings per common share $ 13.25 $ 4.90 $ 6.54 Earnings per common share - assuming dilution: Net income per share - diluted Net income attributable to common stockholders $ 386.1 $ 154.8 $ 213.6 Weighted average common shares outstanding (in thousands) 29,132 31,594 32,674 Common equivalent shares: Share-based awards 394 264 309 Weighted average common shares outstanding - assuming dilution (in thousands) 29,526 31,858 32,983 Earnings per common share assuming dilution $ 13.08 $ 4.86 $ 6.48 We have excluded from the earnings-per-share calculation certain stock options and shares that are considered to be anti-dilutive under the treasury stock method and are reported in the table below. Years ended December 31, Potentially dilutive shares excluded from the calculation as their inclusion would be anti-dilutive 2020 2019 2018 Stock options 75,600 94,600 76,400 Restricted share units 20,137 843 121 Total anti-dilutive shares 95,737 95,443 76,521

Other Financial Information

Other Financial Information	12 Months Ended
Other Financial Information	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Other Financial Information	Other Financial Information CASH FLOW DISCLOSURES — Cash income taxes paid (collected), net of refunds, were $96.5 million, $26.9 million and $17.4 million for the three years ended December 31, 2020, 2019 and 2018, respectively. Interest paid, net of amounts capitalized, was $49.1 million, $56.6 million and $50.4 million for the years ended December 31, 2020, 2019 and 2018, respectively. CHANGES IN WORKING CAPITAL - Years ended December 31, (Millions of dollars) 2020 2019 2018 Accounts receivable $ 4.9 $ (33.4) $ 86.6 Inventories (51.7) (6.1) (39.0) Prepaid expenses and other current assets 16.6 (3.3) 11.4 Accounts payable and accrued liabilities 8.3 (5.9) (56.7) Income taxes payable 8.8 — — Net decrease (increase) in noncash operating working capital $ (13.1) $ (48.7) $ 2.3

Assets and Liabilities Measure

Assets and Liabilities Measure at Fair Value	12 Months Ended
Assets and Liabilities Measure at Fair Value	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Assets and Liabilities Measure at Fair Value	Assets and Liabilities Measured at Fair Value The Company carries certain assets and liabilities at fair value in its Consolidated Balance Sheets. The fair value hierarchy is based on the quality of inputs used to measure fair value, with Level 1 being the highest quality and Level 3 being the lowest quality. Level 1 inputs are quoted prices in active markets for identical assets or liabilities. Level 2 inputs are observable inputs other than quoted prices included within Level 1. Level 3 inputs are unobservable inputs which reflect assumptions about pricing by market participants. At the balance sheet date, the fair value of commodity derivatives contracts was determined using NYMEX quoted values and the value of the Interest rate swap derivative was derived by using level 3 inputs, but the balances for each were immaterial. The carrying value of the Company’s Cash and cash equivalents, Accounts receivable-trade, Trade accounts payable, interest rate swap contracts and accrued liabilities approximates fair value. See also Note 12 "Financial Instruments and Risk Management in these consolidated financial statements for the period ended December 31, 2020, for more information. The following table presents the carrying amounts and estimated fair values of financial instruments held by the Company at December 31, 2020 and 2019. The fair value of a financial instrument is the amount at which the instrument could be exchanged in a current transaction between willing parties. The table excludes Cash and cash equivalents, Accounts receivable-trade, and Trade accounts payable and accrued liabilities, all of which had fair values approximating carrying amounts. The fair value of Current and Long-term debt was estimated based on rates offered to the Company at that time for debt of the same maturities. The Company has off-balance sheet exposures relating to certain financial guarantees and letters of credit. The fair value of these, which represents fees associated with obtaining the instruments, was nominal. December 31, 2020 December 31, 2019 Carrying Carrying (Millions of dollars) Amount Fair Value Amount Fair Value Financial liabilities Current and long-term debt $ (1,002.4) $ (1,029.9) $ (1,038.1) $ (1,069.4)

Commitments

Commitments	12 Months Ended
Commitments	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments	Commitments The Company leases land, gasoline stations, and other facilities under operating leases. During the next five years, expected future rental payments under all operating leases are approximately $16.8 million in 2021, $15.9 million in 2022, $15.4 million in 2023, $14.9 million in 2024, and $14.2 million in 2025. Rental expense for noncancellable operating leases, including contingent payments when applicable, was $24.9 million in 2020, $21.6 million in 2019 and $15.2 million in 2018. Commitments for capital expenditures were approximately $286.8 million at December 31, 2020, including $278.3 million approved for potential construction of future Murphy USA and Murphy Express gasoline stations (including land) at year-end, along with $4.1 million for improvements of existing stations, to be financed with our operating cash flow and/or incurrence of indebtedness.

Contingencies

Contingencies	12 Months Ended
Contingencies	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Contingencies	Contingencies The Company’s operations and earnings have been and may be affected by various forms of governmental action. Examples of such governmental action include, but are by no means limited to: tax increases and retroactive tax claims; import and export controls; price controls; allocation of supplies of crude oil and petroleum products and other goods; laws and regulations intended for the promotion of safety and the protection and/or remediation of the environment; governmental support for other forms of energy; and laws and regulations affecting the Company’s relationships with employees, suppliers, customers, stockholders and others. Because governmental actions are often motivated by political considerations, may be taken without full consideration of their consequences, and may be taken in response to actions of other governments, it is not practical to attempt to predict the likelihood of such actions, the form the actions may take or the effect such actions may have on the Company. ENVIRONMENTAL MATTERS AND LEGAL MATTERS — Murphy USA is subject to numerous federal, state and local laws and regulations dealing with the environment. Violation of such environmental laws, regulations and permits can result in the imposition of significant civil and criminal penalties, injunctions and other sanctions. A discharge of hazardous substances into the environment could, to the extent such event is not insured, subject the Company to substantial expense, including both the cost to comply with applicable regulations and claims by neighboring landowners and other third parties for any personal injury, property damage and other losses that might result. The Company currently owns or leases, and has in the past owned or leased, properties at which hazardous substances have been or are being handled. Although the Company believes it has used operating and disposal practices that were standard in the industry at the time, hazardous substances may have been disposed of or released on or under the properties owned or leased by the Company or on or under other locations where they have been taken for disposal. In addition, many of these properties have been operated by third parties whose management of hazardous substances was not under the Company’s control. Under existing laws, the Company could be required to remediate contaminated property (including contaminated groundwater) or to perform remedial actions to prevent future contamination. Certain of these contaminated properties are in various stages of negotiation, investigation, and/or cleanup, and the Company is investigating the extent of any related liability and the availability of applicable defenses. With the sale of the U.S. refineries in 2011, Murphy Oil retained certain liabilities related to environmental matters. Murphy Oil also obtained insurance covering certain levels of environmental exposures. With respect to the previously owned refinery properties, Murphy Oil retained those liabilities in the Separation and Distribution agreement that was entered into related to the separation on August 30, 2013. With respect to any remaining potential liabilities, the Company believes costs related to these sites will not have a material adverse effect on Murphy USA’s net income, financial position or liquidity in a future period. Certain environmental expenditures are likely to be recovered by the Company from other sources, primarily environmental funds maintained by certain states. Since no assurance can be given that future recoveries from other sources will occur, the Company has not recorded a benefit for likely recoveries at December 31, 2020, however certain jurisdictions provide reimbursement for these expenses which have been considered in recording the net exposure. The U.S. Environmental Protection Agency (EPA) currently considers the Company a Potentially Responsible Party (PRP) at one Superfund site. As to the site, the potential total cost to all parties to perform necessary remedial work at this site may be substantial. However, based on current negotiations and available information, the Company believes that it is a de minimis party as to ultimate responsibility at the Superfund site. Accordingly, the Company has not recorded a liability for remedial costs at the Superfund site at December 31, 2020. The Company could be required to bear a pro rata share of costs attributable to nonparticipating PRPs or could be assigned additional responsibility for remediation at this site or other Superfund sites. The Company believes that its share of the ultimate costs to clean-up this site will be immaterial and will not have a material adverse effect on its net income, financial position or liquidity in a future period. Based on information currently available to the Company, the amount of future remediation costs to be incurred to address known contamination sites is not expected to have a material adverse effect on the Company’s future net income, cash flows or liquidity. However, there is the possibility that additional environmental expenditures could be required to address contamination, including as a result of discovering additional contamination or the imposition of new or revised requirements applicable to known contamination. Murphy USA is engaged in a number of other legal proceedings, all of which the Company considers routine and incidental to its business. Based on information currently available to the Company, the ultimate resolution of those other legal matters is not expected to have a material adverse effect on the Company’s net income, financial condition or liquidity in a future period. INSURANCE — The Company maintains insurance coverage at levels that are customary and consistent with industry standards for companies of similar size. Murphy USA maintains statutory workers compensation insurance with a deductible of $1.0 million per occurrence, general liability insurance with a deductible of $3.0 million per occurrence, and auto liability insurance with a deductible of $0.3 million per occurrence. As of December 31, 2020, there were a number of outstanding claims that are of a routine nature. The estimated incurred but unpaid liabilities relating to these claims are included in Trade account payables and accrued liabilities on the Consolidated Balance Sheets. While the ultimate outcome of these claims cannot presently be determined, management believes that the accrued liability of $27.8 million will be sufficient to cover the related liability and that the ultimate disposition of these claims will have no material effect on the Company’s financial position and results of operations. The Company has obtained insurance coverage as appropriate for the business in which it is engaged, but may incur losses that are not covered by insurance or reserves, in whole or in part, and such losses could adversely affect our results of operations and financial position. TAX MATTERS — Murphy USA is subject to extensive tax liabilities imposed by multiple jurisdictions, including income taxes, indirect taxes (excise/duty, sales/use and gross receipts taxes), payroll taxes, franchise taxes, withholding taxes and ad valorem taxes. New tax laws and regulations and changes in existing tax laws and regulations are continuously being enacted or proposed that could result in increased expenditures for tax liabilities in the future. Many of these liabilities are subject to periodic audits by the respective taxing authority. Subsequent changes to our tax liabilities because of these audits may subject us to interest and penalties. OTHER MATTERS — In the normal course of its business, the Company is required under certain contracts with various governmental authorities and others to provide financial guarantees or letters of credit that may be drawn upon if the Company fails to perform under those contracts. At December 31, 2020, the Company had contingent liabilities of $13.0 million on outstanding letters of credit. The Company has not accrued a liability in its balance sheet related to these financial guarantees and letters of credit because it is believed that the likelihood of having these drawn is remote.

Leases

Leases	12 Months Ended
Leases	Dec. 31, 2020
Leases [Abstract]
Leases	Leases The Company determines if an arrangement is a lease or contains a lease at inception. Operating lease right-of-use assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. Leases with an initial term of 12 months or less are not recorded on the balance sheet; we recognize lease expense for these leases on a straight-line basis over the lease term. The Company's leases have remaining lease terms of approximately 1 year to 20 years, which may include the option to extend the lease when it is reasonably certain the Company will exercise the option. Most leases include one or more options to renew, with renewal terms that can extend the lease term from 5 to 20 years or more. The exercise of lease renewal options is at the Company's sole discretion. Due to the uncertainties of future markets, economic factors, technology changes, demographic shifts and behavior, environmental regulatory requirements and other information that impacts decisions as to station location, management has determined that it was not reasonably certain to exercise contract options and they are not included in the lease term. Additionally, short-term leases and leases with variable lease costs are immaterial. The Company reviews all options to extend, terminate, or otherwise modify its lease agreements to determine if changes are required to the right of use assets and liabilities. As the implicit interest rate is not readily determinable in most of the Company's lease agreements, the Company uses its estimated secured incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. Lessor — We have various arrangements for certain spaces for food service and vending equipment under which we are the lessor. These leases meet the criteria for operating lease classification. Lease income associated with these leases is immaterial. Lessee —We lease land for 232 stations, one terminal, and various equipment. Our lease agreements do not contain any material residual value guarantees and approximately 102 sites leased from Walmart contain restrictive covenants, though the restrictions are deemed to have an immaterial impact. Leases are reflected in the following balance sheet accounts: (Millions of dollars) Classification December 31, December 31, Assets Operating (Right-of-use) Other Assets $ 147.7 $ 124.2 Finance Property, plant, and equipment, at cost, less accumulated depreciation of $2.8 in 2020 and $2.2 in 2019 2.6 3.0 Total leased assets $ 150.3 $ 127.2 (Millions of dollars) Classification December 31, December 31, Liabilities Current Operating Trade accounts payable and accrued liabilities $ 7.8 $ 6.8 Finance Current maturities of long-term debt 1.2 1.2 Noncurrent Operating Deferred credits and other liabilities 142.5 118.5 Finance Long-term debt, including capitalized lease obligations 0.9 1.2 Total lease liabilities $ 152.4 $ 127.7 Lease Cost: Year Ended December 31, (Millions of dollars) Classification 2020 2019 Operating lease cost Station and other operating expenses $ 16.6 $ 14.5 Finance lease cost Amortization of leased assets Depreciation & amortization expense 1.3 1.2 Interest on lease liabilities Interest expense 0.1 0.1 Net lease costs $ 18.0 $ 15.8 Cash flow information: Year Ended December 31, (Millions of dollars) 2020 2019 Cash paid for amounts included in the measurement of liabilities Operating cash flows required by operating leases $ 15.5 $ 13.8 Operating cash flows required by finance leases $ 0.1 $ 0.1 Financing cash flows required by finance leases $ 1.4 $ 1.4 Maturity of Lease Liabilities: (Millions of dollars) Operating leases Finance leases 2021 $ 16.8 $ 1.2 2022 15.9 0.7 2023 15.4 0.3 2024 14.9 — 2025 14.2 — After 2025 166.9 — Total lease payments 244.1 2.2 less: interest 93.8 0.1 Present value of lease liabilities $ 150.3 $ 2.1 Lease Term and Discount Rate: Year Ended December 31, 2020 Weighted average remaining lease term (years) Finance leases 2.0 Operating leases 15.7 Weighted average discount rate Finance leases 4.2 % Operating leases 5.7 %
Leases	Leases The Company determines if an arrangement is a lease or contains a lease at inception. Operating lease right-of-use assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. Leases with an initial term of 12 months or less are not recorded on the balance sheet; we recognize lease expense for these leases on a straight-line basis over the lease term. The Company's leases have remaining lease terms of approximately 1 year to 20 years, which may include the option to extend the lease when it is reasonably certain the Company will exercise the option. Most leases include one or more options to renew, with renewal terms that can extend the lease term from 5 to 20 years or more. The exercise of lease renewal options is at the Company's sole discretion. Due to the uncertainties of future markets, economic factors, technology changes, demographic shifts and behavior, environmental regulatory requirements and other information that impacts decisions as to station location, management has determined that it was not reasonably certain to exercise contract options and they are not included in the lease term. Additionally, short-term leases and leases with variable lease costs are immaterial. The Company reviews all options to extend, terminate, or otherwise modify its lease agreements to determine if changes are required to the right of use assets and liabilities. As the implicit interest rate is not readily determinable in most of the Company's lease agreements, the Company uses its estimated secured incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. Lessor — We have various arrangements for certain spaces for food service and vending equipment under which we are the lessor. These leases meet the criteria for operating lease classification. Lease income associated with these leases is immaterial. Lessee —We lease land for 232 stations, one terminal, and various equipment. Our lease agreements do not contain any material residual value guarantees and approximately 102 sites leased from Walmart contain restrictive covenants, though the restrictions are deemed to have an immaterial impact. Leases are reflected in the following balance sheet accounts: (Millions of dollars) Classification December 31, December 31, Assets Operating (Right-of-use) Other Assets $ 147.7 $ 124.2 Finance Property, plant, and equipment, at cost, less accumulated depreciation of $2.8 in 2020 and $2.2 in 2019 2.6 3.0 Total leased assets $ 150.3 $ 127.2 (Millions of dollars) Classification December 31, December 31, Liabilities Current Operating Trade accounts payable and accrued liabilities $ 7.8 $ 6.8 Finance Current maturities of long-term debt 1.2 1.2 Noncurrent Operating Deferred credits and other liabilities 142.5 118.5 Finance Long-term debt, including capitalized lease obligations 0.9 1.2 Total lease liabilities $ 152.4 $ 127.7 Lease Cost: Year Ended December 31, (Millions of dollars) Classification 2020 2019 Operating lease cost Station and other operating expenses $ 16.6 $ 14.5 Finance lease cost Amortization of leased assets Depreciation & amortization expense 1.3 1.2 Interest on lease liabilities Interest expense 0.1 0.1 Net lease costs $ 18.0 $ 15.8 Cash flow information: Year Ended December 31, (Millions of dollars) 2020 2019 Cash paid for amounts included in the measurement of liabilities Operating cash flows required by operating leases $ 15.5 $ 13.8 Operating cash flows required by finance leases $ 0.1 $ 0.1 Financing cash flows required by finance leases $ 1.4 $ 1.4 Maturity of Lease Liabilities: (Millions of dollars) Operating leases Finance leases 2021 $ 16.8 $ 1.2 2022 15.9 0.7 2023 15.4 0.3 2024 14.9 — 2025 14.2 — After 2025 166.9 — Total lease payments 244.1 2.2 less: interest 93.8 0.1 Present value of lease liabilities $ 150.3 $ 2.1 Lease Term and Discount Rate: Year Ended December 31, 2020 Weighted average remaining lease term (years) Finance leases 2.0 Operating leases 15.7 Weighted average discount rate Finance leases 4.2 % Operating leases 5.7 %

Recent Accounting and Reporting

Recent Accounting and Reporting Rules	12 Months Ended
Recent Accounting and Reporting Rules	Dec. 31, 2020
Accounting Standards Update and Change in Accounting Principle [Abstract]
Recent Accounting and Reporting Rules	Recent Accounting and Reporting Rules In June 2016, the FASB issued ASU 2016-13, "Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments." ASU 2016-13 was subsequently modified by ASU 2018-19, ASU 2019-04, ASU 2019-05, and ASU 2019-11. This ASU changed the way entities recognize impairment of many financial assets by requiring immediate recognition of estimated credit losses expected to occur over their remaining life, which will result in timelier recognition of losses. ASU 2016-13 and the associated modifications was effective for the Company on January 1, 2020 and required a modified retrospective approach with an adjustment at the beginning of year for any adjustment due to its adoption. In applying ASC 326 at January 1, 2020, the Company calculated an adjustment to its estimated credit loss allowance and lowered the allowance by $1.1 million, which was credited to retained earnings under the modified retrospective approach. The adjustment reflects the Company's changes in credit practices since its spin-of in 2013 which includes tighter applied credit terms and faster turnover of receivables resulting in a decrease to its estimated credit loss allowance as of January 1, 2020. In August 2018, the FASB issued ASU 2018-15, "Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract". This ASU aligns the accounting treatment for capitalizing implementation costs incurred by customers in cloud computing arrangements in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. This guidance was effective for the Company on January 1, 2020. The amendments in this update were applied prospectively to all implementation costs incurred after the date of adoption. The Company assessed the effect that this ASU had on our financial position, results of operations, and disclosures and determined that this update did not have a material impact on the Company's consolidated financial statements. In August 2018, the FASB issued ASU 2018-13, "Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement". This ASU eliminated, amended, and added disclosure requirements for fair value measurements in Topic 820, including disclosing the changes in unrealized gains and losses for the period included in other comprehensive income for level 3 measurements. This guidance was effective for the Company on January 1, 2020. The Company assessed the effect that this ASU had on our financial position, results of operations, and disclosures and determined that this update did not have a material impact on the Company's consolidated financial statements. See Note 12 "Financial Instruments and Risk Management" for additional information. In December 2019, the FASB issued ASU 2019-12, "Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes," which removes certain exceptions for: recognizing deferred taxes on investments, performing intraperiod allocation and calculating income taxes for interim periods. The ASU also adds guidance to reduce complexity in certain areas, including recognizing deferred taxes for tax goodwill and allocating taxes to members of a consolidated group. This ASU is effective for the Company for the year beginning January 1, 2021, and early adoption is permitted. The Company has assessed the effect that this ASU will have on our financial position, results of operations, and disclosures and has concluded that this update will not have a material impact on the Company's consolidated financial statements.

Business Segments

Business Segments	12 Months Ended
Business Segments	Dec. 31, 2020
Segment Reporting [Abstract]
Business Segments	Business Segments Our operations include the sale of retail motor fuel products and convenience merchandise along with the wholesale and bulk sale capabilities of our product supply and wholesale group. As the primary purpose of the product supply and wholesale group is to support our retail operations and provide fuel for their daily operation, the bulk and wholesale fuel sales are secondary to the support functions played by these groups. As such, they are all treated as one segment for reporting purposes as they sell the same products. This Marketing segment contains essentially all of the revenue generating activities of the Company. Results not included in the reportable segment include Corporate and Other Assets. The reportable segment was determined based on information reviewed by the Chief Operating Decision Maker. Segment Information Corporate and Other Assets (Millions of dollars) Marketing Consolidated Year ended December 31, 2020 Segment income (loss) $ 442.2 $ (56.1) $ 386.1 Revenues from external customers $ 11,264.0 $ 0.3 $ 11,264.3 Interest income $ — $ 1.0 $ 1.0 Interest expense $ (0.1) $ (51.1) $ (51.2) Loss on early debt extinguishment $ — $ — $ — Income tax expense (benefit) $ 132.9 $ (9.9) $ 123.0 Significant noncash charges (credits) Depreciation and amortization $ 146.3 $ 14.7 $ 161.0 Accretion of asset retirement obligations $ 2.3 $ — $ 2.3 Debt extinguishment costs $ — $ — $ — Deferred and noncurrent income taxes (benefits) $ 2.8 $ (0.3) $ 2.5 Additions to property, plant and equipment $ 200.8 $ 26.3 $ 227.1 Total assets at year-end $ 2,418.2 $ 267.5 $ 2,685.7 Segment Information Corporate and Other Assets (Millions of dollars) Marketing Consolidated Year ended December 31, 2019 Segment income (loss) $ 215.0 $ (60.2) $ 154.8 Revenues from external customers $ 14,034.3 $ 0.3 $ 14,034.6 Interest income $ — $ 3.2 $ 3.2 Interest expense $ (0.1) $ (54.8) $ (54.9) Loss on early debt extinguishment $ — $ (14.8) $ (14.8) Income tax expense (benefit) $ 66.3 $ (18.7) $ 47.6 Significant noncash charges (credits) Depreciation and amortization $ 138.9 $ 13.3 $ 152.2 Accretion of asset retirement obligations $ 2.1 $ — $ 2.1 Debt extinguishment costs $ — $ 4.4 $ 4.4 Deferred and noncurrent income taxes (benefits) $ 32.9 $ (9.2) $ 23.7 Additions to property, plant and equipment $ 155.5 $ 59.1 $ 214.6 Total assets at year-end $ 2,304.7 $ 382.5 $ 2,687.2 Segment Information Corporate and Other Assets (Millions of dollars) Marketing Consolidated Year ended December 31, 2018 Segment income (loss) $ 214.2 $ (0.6) $ 213.6 Revenues from external customers $ 14,362.3 $ 0.6 $ 14,362.9 Interest income $ — $ 1.5 $ 1.5 Interest expense $ (0.1) $ (52.8) $ (52.9) Income tax expense (benefit) $ 69.5 $ (9.2) $ 60.3 Significant noncash charges (credits) Depreciation and amortization $ 124.5 $ 9.5 $ 134.0 Accretion of asset retirement obligations $ 2.0 $ — $ 2.0 Deferred and noncurrent income taxes (benefits) $ 39.0 $ (1.1) $ 37.9 Additions to property, plant and equipment $ 169.2 $ 24.6 $ 193.8 Total assets at year-end $ 2,012.0 $ 348.8 $ 2,360.8

Subsequent Event (Notes)

Subsequent Event (Notes)	12 Months Ended
Subsequent Event (Notes)	Dec. 31, 2020
Subsequent Events [Abstract]
Subsequent Event	Subsequent Events On January 29, 2021, the Company completed its acquisition of QuickChek, a chain of convenience stores located primarily in New Jersey and New York by purchasing 100% of the outstanding equity for an all-cash consideration of $645 million before adjustments for working capital and other customary items. Due to the close proximity of the completion of the acquisition to the filing of this Form 10-K, the Company is unable to provide a preliminary purchase price allocation of the fair value of assets acquired and liabilities assumed in the transaction. The Company will disclose a preliminary purchase price allocation in its Form 10-Q for the period ending March 31, 2021. The financial results for QuickChek will be included in the Company's consolidated financial statements from the date of acquisition. Also, on January 29, 2021, the Company refinanced its existing credit facility and issued new senior unsecured notes. The Company entered into a new credit agreement that provides for a secured term loan of $400 million (which was borrowed in full) and revolving credit commitments of $350 million. The term loan expires seven years from the date of issuance and the revolving credit facility matures in five years. The secured term loan accrues interest at LIBOR plus 1.75%, subject to a LIBOR floor of 0.50% and the revolving credit facility accrues interest, when drawn, at LIBOR plus a range of 1.75% to 2.25% depending on a total debt to EBITDA ratio covenant. As part of entering into the new credit agreement, the prior agreement which consisted of an ABL facility and term loan was fully repaid and retired.

Schedule II - Valuation And Qua

Schedule II - Valuation And Qualifying Accounts	12 Months Ended
Schedule II - Valuation And Qualifying Accounts	Dec. 31, 2020
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Schedule II - Valuation And Qualifying Accounts	SCHEDULE II – VALUATION AND QUALIFYING ACCOUNTS Murphy USA Inc. Valuation Accounts and Reserves (Millions of dollars) Balance at January 1, Charged (Credited) to Expense Deductions Balance at December 31, 2020 Deducted from assets accounts Allowance for doubtful accounts $ 1.2 — (1.1) $ 0.1 2019 Deducted from assets accounts Allowance for doubtful accounts $ 1.1 0.1 $ 1.2 2018 Deducted from assets accounts Allowance for doubtful accounts $ 1.1 0.5 (0.5) $ 1.1

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	12 Months Ended
Significant Accounting Policies (Policies)	Dec. 31, 2020
Accounting Policies [Abstract]
Principles of Consolidation	PRINCIPLES OF CONSOLIDATION – These consolidated financial statements were prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) and include the accounts of Murphy USA Inc. and its subsidiaries for all periods presented. All significant intercompany accounts and transactions within the consolidated financial statements have been eliminated.
Revenue Recognition, Shipping and Handling Costs and Vendor Allowances and Rebates	REVENUE RECOGNITION – Revenue is recognized when obligations under the terms of a contract with our customers are satisfied; generally, this occurs with the transfer of control of our petroleum products, convenience merchandise, Renewable Identification Numbers ("RINs") and other assets to our third-party customers. Revenue is measured as the amounts of consideration we expect to receive in exchange for transferring goods or providing services. Excise and sales tax that we collect where we have determined we are the principal in the transaction have been recorded as revenue on a jurisdiction-by-jurisdiction basis. The Company enters into buy/sell and similar arrangements when petroleum products are held at one location but are needed at a different location. The Company often pays or receives funds related to the buy/sell arrangement based on location or quality differences. The Company accounts for such transactions on a net basis in its Consolidated Income Statements. See Note 3 "Revenues" for additional information. SHIPPING AND HANDLING COSTS – Costs incurred for the shipping and handling of motor fuel are included in Petroleum product cost of goods sold in the Consolidated Income Statements. Costs incurred for the shipping and handling of convenience store merchandise are included in Merchandise cost of goods sold in the Consolidated Income Statements. Petroleum product sales (at retail). For our retail store locations, the revenue related to petroleum product sales is recognized as the fuel is pumped to our customers. The transaction price at the pump typically includes some portion of sales or excise taxes as levied in the respective jurisdictions. Those taxes that are collected for remittance to governmental entities on a pass through basis are not recognized as revenue and they are recorded to a liability account until they are paid. Our customers typically use a mixture of cash, checks, credit cards and debit cards to pay for our products as they are received. We have accounts receivable from the various credit/debit card providers at any point in time related to product sales made on credit cards and debit cards. These receivables are typically collected in two Petroleum product sales (at wholesale). Our sales of petroleum products at wholesale are generally recorded as revenue when the deliveries have occurred and legal ownership of the product has transferred to the customer. Title transfer for bulk refined product sales typically occurs at pipeline custody points and upon trucks loading at product terminals. For bulk pipeline sales, we record receivables from customers that are generally collected within a week from custody transfer date. For our rack product sales, the majority of our customers' accounts are drafted by us within 10 days from product transfer. Merchandise sales. For our retail store locations, the revenue related to merchandise sales is recognized as the customer completes their purchase at our locations. The transaction price typically includes some portion of sales tax as levied in the respective jurisdictions. Those taxes that are collected for remittance to governmental entities on a pass through basis are not recognized as revenue and they are recorded to a liability account until they are paid. As noted above, a mixture of payment types are used for these revenues and the same terms for credit/debit card receivables are realized. The most significant judgment with respect to merchandise sales revenue is determining whether we are the principal or agent for some categories of merchandise such as lottery tickets, lotto tickets, newspapers and other small categories of merchandise. For scratch-off lottery tickets, we have determined we are the principal in the majority of the jurisdictions and therefore we record those sales on a gross basis. We have some categories of merchandise (such as lotto tickets) where we are the agent and the revenues recorded for those transactions are our net commission only. In June 2018 the Company initiated a loyalty pilot program through a limited number of its retail locations and was rolled out chain-wide in March 2019. The customers earn rewards based on their spending or other promotional activities. This program creates a performance obligation which requires us to defer a portion of sales revenue to the loyalty program participants until they redeem their rewards. The rewards may be redeemed for free or discounted merchandise or cash discounts on fuel purchases. Earned rewards expire after an account is inactive for a period of 90 days. We recognize loyalty revenue when a customer redeems an earned reward. Deferred revenue associated with Murphy Rewards is included in Trade accounts payable and accrued liabilities in our Consolidated Balance Sheet. The deferred revenues recorded in 2020 and 2019 were immaterial. RINs sales. For the sale of RINs, we recognize revenue when the RIN is transferred to the counter-party and the sale is completed. Receivables from our counter-parties related to the RIN sales are typically collected within five days of the sale. Other revenues. Items reported as other operating revenues include collection allowances for excise and sales tax and other miscellaneous items and are recognized as revenue when the transaction is completed.
Taxes Collected from Customers and Remitted to Government Authorities	TAXES COLLECTED FROM CUSTOMERS AND REMITTED TO GOVERNMENT AUTHORITIES – Excise and other taxes collected on sales of refined products and remitted to governmental agencies are included in operating revenues and operating expenses in the Consolidated Income Statements.
Cash Equivalents	CASH EQUIVALENTS – Short-term investments, which include government securities, money market funds and other instruments with government securities as collateral, that have a maturity of three months or less from the date of purchase are classified as cash equivalents.
Accounts Receivable	ACCOUNTS RECEIVABLE – The Company’s accounts receivable are recorded at the invoiced amount and do not bear interest. The accounts receivable primarily consists of amounts owed to the Company from credit card companies and by customers for wholesale sales of refined petroleum products. The allowance for doubtful accounts is the Company’s best estimate of the amount of probable credit losses on these receivables. The Company reviews this allowance for adequacy at least quarterly and bases its assessment on a combination of current information about its customers and historical write-off experience. Any trade accounts receivable balances written off are charged against the allowance for doubtful accounts. The Company has not experienced any significant credit-related losses in the past three years.
Inventories	INVENTORIES – Inventories of most finished products are valued at the lower of cost, generally applied on a last-in, first-out (“LIFO”) basis, or market. Any increments to LIFO inventory volumes are valued based on the first purchase price for these volumes during the year. Merchandise inventories held for resale are carried at average cost. Materials and supplies are valued at the lower of average cost or estimated value.
Property, Plant and Equipment	PROPERTY, PLANT AND EQUIPMENT – Additions to property, plant and equipment, including renewals and betterments, are capitalized and recorded at cost. Certain marketing facilities are primarily depreciated using the composite straight-line method with depreciable lives ranging from 16 to 25 years. Gasoline stations, improvements to gasoline stations and other assets are depreciated over 3 to 50 years by individual unit on the straight-line method. The Company capitalizes interest costs as a component of construction in progress on individually significant projects based on the weighted average interest rates incurred on its long-term borrowings. Total interest cost capitalized was $1.4 million in 2020 and 2019, respectfully and $2.2 million in 2018. The Company has undertaken like-kind exchange ("LKE") transactions under the Federal tax code in an effort to acquire and sell real and personal property in a tax efficient manner. The Company generally enters into forward transactions, in which property is sold and the proceeds are reinvested by acquiring similar property; and reverse transactions, in which property is acquired and similar property is subsequently sold. A qualified LKE intermediary is used to facilitate these LKE transactions. Proceeds from forward LKE transactions are held by the intermediary and are classified as restricted cash on the Company's balance sheet because the funds must be reinvested in similar properties. If the acquisition of suitable LKE properties is not completed within 180 days of the sale of the Company-owned property, the proceeds are distributed to the Company by the intermediary and are reclassified as available cash and applicable income taxes are determined. An exchange accommodation titleholder, a type of variable interest entity, is used to facilitate reverse like-kind exchanges. The acquired assets are held by the exchange accommodation titleholder until the exchange transactions are complete. If the Company determines that it is the primary beneficiary of the exchange accommodation titleholder, the replacements assets held by the exchange accommodation titleholder are consolidated and recorded in Property, Plant and Equipment on the Consolidated Balance Sheets. The unspent proceeds that are held in trust with the intermediary are recorded as noncurrent assets in the Consolidated Balance Sheet as the cash was restricted for the acquisition of property, plant and equipment.
Impairment of Assets	IMPAIRMENT OF ASSETS – Long-lived assets, which include property and equipment and finite-lived intangible assets, are tested for recoverability whenever events or changes in circumstances indicate that the carrying amount of the asset may not be recoverable. A long-lived asset is not recoverable if its carrying amount exceeds the sum of the undiscounted cash flows expected to result from its use and eventual disposition. If a long-lived asset is not recoverable, an impairment loss is recognized for the amount by which the carrying amount of the long-lived asset exceeds its fair value, with fair value determined based on discounted estimated net cash flows or other appropriate methods.
Asset Retirement Obligations	ASSET RETIREMENT OBLIGATIONS – The Company records a liability for asset retirement obligations (“ARO”) equal to the fair value of the estimated cost to retire an asset. The ARO liability is initially recorded in the period in which the obligation meets the definition of a liability, which is generally when the asset is placed in service. The ARO liability is estimated using existing regulatory requirements and anticipated future inflation rates. When the liability is initially recorded, the Company increases the carrying amount of the related long-lived asset by an amount equal to the original liability. The liability is increased over time to reflect the change in its present value, and the capitalized cost is depreciated over the useful life of the related long-lived asset. The Company reevaluates the adequacy of its recorded ARO liability at least annually. Actual costs of asset retirements such as dismantling service stations and site restoration are charged against the related liability. Any difference between costs incurred upon settlement of an asset retirement obligation and the recorded liability is recognized as a gain or loss in the Company’s Consolidated Income Statements.
Environmental Liabilities	ENVIRONMENTAL LIABILITIES – A liability for environmental matters is established when it is probable that an environmental obligation exists and the cost can be reasonably estimated. If there is a range of reasonably estimated costs, the most likely amount will be recorded, or if no amount is most likely, the minimum of the range is used. Related expenditures are charged against the liability. Environmental remediation liabilities have not been discounted for the time value of future expected payments. Environmental expenditures that have future economic benefit are capitalized.
Income Taxes	INCOME TAXES – The Company accounts for income taxes using the asset and liability method. Under this method, income taxes are provided for amounts currently payable and for amounts deferred as tax assets and liabilities based on differences between the financial statement carrying amounts and the tax bases of existing assets and liabilities. Deferred income taxes are measured using the enacted tax rates that are assumed will be in effect when the differences reverse. The Company routinely assesses the realizability of deferred tax assets based on available positive and negative evidence including assumptions of future taxable income, tax planning strategies and other pertinent factors. A deferred tax asset valuation allowance is recorded when evidence indicates that it is more likely than not that all or a portion of these deferred tax assets will not be realized in a future period. The accounting principles for income tax uncertainties permit recognition of income tax benefits only when they are more likely than not to be realized. The Company has elected to classify any interest expense and penalties related to the underpayment of income taxes in Income tax expense in the Consolidated Income Statements.
Derivative Instruments and Hedging Activities	DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES – The fair value of a derivative instrument is recognized as an asset or liability in the Company’s Consolidated Balance Sheets. Upon entering into a derivative contract, the Company may designate the derivative as either a fair value hedge or a cash flow hedge, or decide that the contract is not a hedge, and therefore, recognize changes in the fair value of the contract in earnings. The Company documents the relationship between the derivative instrument designated as a hedge and the hedged items as well as its objective for risk management and strategy for use of the hedging instrument to manage the risk. Derivative instruments designated as fair value or cash flow hedges are linked to specific assets and liabilities or to specific firm commitments or forecasted transactions. The Company assesses at inception and on an ongoing basis whether a derivative instrument accounted for as a hedge is highly effective in offsetting changes in the fair value or cash flows of the hedged item. A derivative that is not a highly effective hedge does not qualify for hedge accounting. The change in the fair value of a qualifying fair value hedge is recorded in earnings along with the gain or loss on the hedged item. The effective portion of the change in the fair value of a qualifying cash flow hedge is recorded in Accumulated other comprehensive income (AOCI) in the consolidated Balance Sheets until the hedged item is recognized currently in earnings. If a derivative instrument no longer qualifies as a cash flow hedge and the underlying forecasted transaction is no longer probable of occurring, hedge accounting is discontinued and the gain or loss recorded in Accumulated other comprehensive income is recognized immediately in earnings.
Stock-Based Compensation	STOCK-BASED COMPENSATION – The fair value of awarded stock options, restricted stock, restricted stock units and performance stock units is determined based on a combination of management assumptions for awards issued. The Company uses the Black-Scholes option pricing model for computing the fair value of stock options. The primary assumptions made by management included the expected life of the stock option award and the expected volatility of the Company’s common stock prices. The Company uses both historical data and current information to support its assumptions. Stock option expense is recognized on a straight-line basis over the requisite service period of three years. The Company uses a Monte Carlo valuation model to determine the fair value of performance-based stock units that are based on performance compared against a peer group and the related expense is recognized over the
Use of Estimates	USE OF ESTIMATES – In preparing the financial statements of the Company in conformity with U.S. GAAP, management has made a number of estimates and assumptions related to the reporting of assets, liabilities, revenues, and expenses and the disclosure of contingent assets and liabilities. Actual results may differ from the estimates. On an ongoing basis, we review our estimates based on currently available information. Changes in facts and circumstances may result in revised estimates.
Recent Accounting and Reporting Rules	Recent Accounting and Reporting Rules In June 2016, the FASB issued ASU 2016-13, "Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments." ASU 2016-13 was subsequently modified by ASU 2018-19, ASU 2019-04, ASU 2019-05, and ASU 2019-11. This ASU changed the way entities recognize impairment of many financial assets by requiring immediate recognition of estimated credit losses expected to occur over their remaining life, which will result in timelier recognition of losses. ASU 2016-13 and the associated modifications was effective for the Company on January 1, 2020 and required a modified retrospective approach with an adjustment at the beginning of year for any adjustment due to its adoption. In applying ASC 326 at January 1, 2020, the Company calculated an adjustment to its estimated credit loss allowance and lowered the allowance by $1.1 million, which was credited to retained earnings under the modified retrospective approach. The adjustment reflects the Company's changes in credit practices since its spin-of in 2013 which includes tighter applied credit terms and faster turnover of receivables resulting in a decrease to its estimated credit loss allowance as of January 1, 2020. In August 2018, the FASB issued ASU 2018-15, "Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract". This ASU aligns the accounting treatment for capitalizing implementation costs incurred by customers in cloud computing arrangements in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. This guidance was effective for the Company on January 1, 2020. The amendments in this update were applied prospectively to all implementation costs incurred after the date of adoption. The Company assessed the effect that this ASU had on our financial position, results of operations, and disclosures and determined that this update did not have a material impact on the Company's consolidated financial statements. In August 2018, the FASB issued ASU 2018-13, "Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement". This ASU eliminated, amended, and added disclosure requirements for fair value measurements in Topic 820, including disclosing the changes in unrealized gains and losses for the period included in other comprehensive income for level 3 measurements. This guidance was effective for the Company on January 1, 2020. The Company assessed the effect that this ASU had on our financial position, results of operations, and disclosures and determined that this update did not have a material impact on the Company's consolidated financial statements. See Note 12 "Financial Instruments and Risk Management" for additional information. In December 2019, the FASB issued ASU 2019-12, "Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes," which removes certain exceptions for: recognizing deferred taxes on investments, performing intraperiod allocation and calculating income taxes for interim periods. The ASU also adds guidance to reduce complexity in certain areas, including recognizing deferred taxes for tax goodwill and allocating taxes to members of a consolidated group. This ASU is effective for the Company for the year beginning January 1, 2021, and early adoption is permitted. The Company has assessed the effect that this ASU will have on our financial position, results of operations, and disclosures and has concluded that this update will not have a material impact on the Company's consolidated financial statements.
Lease Accounting	The Company determines if an arrangement is a lease or contains a lease at inception. Operating lease right-of-use assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. Leases with an initial term of 12 months or less are not recorded on the balance sheet; we recognize lease expense for these leases on a straight-line basis over the lease term. The Company's leases have remaining lease terms of approximately 1 year to 20 years, which may include the option to extend the lease when it is reasonably certain the Company will exercise the option. Most leases include one or more options to renew, with renewal terms that can extend the lease term from 5 to 20 years or more. The exercise of lease renewal options is at the Company's sole discretion. Due to the uncertainties of future markets, economic factors, technology changes, demographic shifts and behavior, environmental regulatory requirements and other information that impacts decisions as to station location, management has determined that it was not reasonably certain to exercise contract options and they are not included in the lease term. Additionally, short-term leases and leases with variable lease costs are immaterial. The Company reviews all options to extend, terminate, or otherwise modify its lease agreements to determine if changes are required to the right of use assets and liabilities.As the implicit interest rate is not readily determinable in most of the Company's lease agreements, the Company uses its estimated secured incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments.

Revenues (Tables)

Revenues (Tables)	12 Months Ended
Revenues (Tables)	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following table disaggregates our revenue by major source for the years ended December 31, 2020, 2019, and 2018. Years Ended December 31, (Millions of dollars) 2020 2019 2018 Marketing Segment Petroleum product sales (at retail) 1 $ 7,444.6 $ 10,184.0 $ 10,459.2 Petroleum product sales (at wholesale) 1 764.0 1,189.8 1,399.2 Total petroleum product sales 8,208.6 11,373.8 11,858.4 Merchandise sales 2,955.1 2,620.1 2,423.0 Other operating revenues: RINs 95.5 34.8 75.2 Other revenues 2 4.8 5.6 5.7 Total marketing segment revenues 11,264.0 14,034.3 $ 14,362.3 Corporate and Other Assets 0.3 0.3 $ 0.6 Total revenues $ 11,264.3 $ 14,034.6 $ 14,362.9 1 Includes excise and sales taxes that remain eligible for inclusion under Topic 606 2 Primarily includes collection allowance on excise and sales taxes and other miscellaneous items

Inventories (Tables)

Inventories (Tables)	12 Months Ended
Inventories (Tables)	Dec. 31, 2020
Inventory Disclosure [Abstract]
Summary of Inventory	Inventories consisted of the following: December 31, (Millions of dollars) 2020 2019 Finished products - FIFO basis $ 223.0 $ 259.2 Less LIFO reserve - finished products (101.3) (160.8) Finished products - LIFO basis 121.7 98.4 Store merchandise for resale 152.0 123.0 Materials and supplies 5.4 6.2 Total inventories $ 279.1 $ 227.6

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
Property, Plant and Equipment (Tables)	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Summary of Property, Plant and Equipment	December 31, 2020 December 31, 2019 (Millions of dollars) Estimated Useful Life Cost Net Cost Net Land $ 609.5 $ 609.5 $ 598.6 $ 598.6 Pipeline and terminal facilities 16 to 25 years 79.8 43.5 77.5 43.7 Retail gasoline stations 3 to 50 years 2,179.7 1,123.2 2,034.4 1,073.6 Buildings 20 to 45 years 66.7 48.5 60.5 44.9 Other 3 to 20 years 123.3 42.9 115.5 46.5 $ 3,059.0 $ 1,867.6 $ 2,886.5 $ 1,807.3

Accounts Payable And Accrued _2

Accounts Payable And Accrued Liabilities (Tables)	12 Months Ended
Accounts Payable And Accrued Liabilities (Tables)	Dec. 31, 2020
Payables and Accruals [Abstract]
Schedule of Accounts Payable and Accrued Liabilities	Trade accounts payable and accrued liabilities consisted of the following: December 31, (Millions of dollars) 2020 2019 Trade accounts payable $ 261.0 $ 280.8 Excise taxes/withholdings payable 84.1 86.2 Accrued insurance obligations 30.3 24.4 Accrued taxes other than income 31.7 25.6 Accrued compensation and benefits 32.5 26.5 Other 31.5 22.7 Accounts payable and accrued liabilities $ 471.1 $ 466.2

Long-Term Debt (Tables)

Long-Term Debt (Tables)	12 Months Ended
Long-Term Debt (Tables)	Dec. 31, 2020
Debt Disclosure [Abstract]
Summary of Long-Term Debt	Long-term debt consisted of the following: December 31, (Millions of dollars) 2020 2019 5.625% senior notes due 2027 (net of unamortized discount of $2.4 at 2020 and $2.7 at 2019) 297.6 297.3 4.75% senior notes due 2029 (net of unamortized discount of $5.4 at 2020 and $6.1 at 2019) 494.6 493.9 Term loan due 2023 (effective interest rate of 2.67% at 2020 and 4.31% at 2019) 212.5 250.0 Capitalized lease obligations, vehicles, due through 2024 2.1 2.4 Unamortized debt issuance costs (4.4) (5.5) Total long-term debt 1,002.4 1,038.1 Less current maturities 51.2 38.8 Total long-term debt, net of current $ 951.2 $ 999.3

Asset Retirement Obligations _2

Asset Retirement Obligations (ARO) (Tables)	12 Months Ended
Asset Retirement Obligations (ARO) (Tables)	Dec. 31, 2020
Asset Retirement Obligation Disclosure [Abstract]
Reconciliation of Beginning and Ending Aggregate Carrying Amount of Asset Retirement Obligation	A reconciliation of the beginning and ending aggregate carrying amount of the ARO is shown in the following table. December 31, (Millions of dollars) 2020 2019 Balance at beginning of period $ 32.8 $ 30.7 Accretion expense 2.3 2.1 Settlement of liabilities (0.8) (0.4) Liabilities incurred 0.8 0.4 Balance at end of period $ 35.1 $ 32.8

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
Income Taxes (Tables)	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Summary of Effective Income Tax Rates	The components of income before income taxes for each of the three years ended December 31, 2020 and income tax expense (benefit) attributable thereto were as follows: Years Ended December 31, (Millions of dollars) 2020 2019 2018 Income (loss) before income taxes $ 509.1 $ 202.4 $ 273.9 Income tax expense (benefit) Federal - Current $ 96.0 15.6 18.4 Federal - Deferred 4.7 21.7 31.0 State - Current and deferred 22.3 10.3 10.9 Total $ 123.0 $ 47.6 $ 60.3
Schedule of Reconciliation of Income Taxes to Statutory Rate	The following table reconciles income taxes based on the U.S. statutory tax rate to the Company’s income tax expense (benefit). Years Ended December 31, (Millions of dollars) 2020 2019 2018 Income tax expense based on the U.S. statutory tax rate $ 106.9 $ 42.5 $ 57.5 State income taxes, net of federal benefit 17.5 8.6 8.3 Federal credits (1.9) (2.3) (2.0) Other, net 0.5 (1.2) (3.5) Total $ 123.0 $ 47.6 $ 60.3
Summary of Deferred Tax Assets and Deferred Tax Liabilities	An analysis of the Company’s deferred tax assets and deferred tax liabilities at December 31, 2020 and 2019 showing the tax effects of significant temporary differences is as follows: December 31, (Millions of dollars) 2020 2019 Deferred tax assets Property costs and asset retirement obligations $ 4.5 $ 3.7 Employee benefits 8.0 6.1 Operating leases liability 31.6 25.0 Other deferred tax assets 7.2 2.1 Total gross deferred tax assets 51.3 36.9 Deferred tax liabilities Accumulated depreciation and amortization (213.2) (191.2) State deferred taxes (20.2) (27.9) Operating leases right of use assets (31.0) (24.8) Other deferred tax liabilities (5.3) (9.7) Total gross deferred tax liabilities (269.7) (253.6) Net deferred tax liabilities $ (218.4) $ (216.7)
Reconciliation of Beginning and Ending Liability for Uncertain Tax Positions	A reconciliation of the beginning and ending amount of the consolidated liability for unrecognized income tax benefits during the year ended December 31, 2020 and 2019 is shown in the following table. Year Ended December 31, (Millions of dollars) 2020 2019 Balance at January 1 $ 0.6 $ 0.7 Additions for tax positions related to prior years 0.1 0.5 Settlements with taxing authorities (0.3) (0.6) Balance at December 31 $ 0.4 $ 0.6

Incentive Plans (Tables)

Incentive Plans (Tables)	12 Months Ended
Incentive Plans (Tables)	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Summary of Amounts Recognized in Financial Statements with Respect to Share-Based Plans	Amounts recognized in the financial statements by the Company with respect to all share-based plans are shown in the following table. Years Ended December 31, (Millions of dollars) 2020 2019 2018 Compensation charged against income before income tax benefit $ 14.3 $ 10.5 $ 9.2 Related income tax benefit recognized in income $ 3.0 $ 2.2 $ 1.9
Summary of Valuation Assumptions	Following are the assumptions used by the Company to value the original awards: Years Ended December 31, 2020 2019 2018 Fair value per option grant $ 28.28 $ 20.48 $ 17.32 Assumptions Dividend yield — — — Expected volatility 28.1 % 26.8 % 27.0 % Risk-free interest rate 1.5 % 2.5 % 2.4 % Expected life (years) 4.7 4.5 3.9 Stock price at valuation date $ 106.72 $ 76.15 $ 71.00
Summary of Changes in Stock Options Outstanding	Changes in options outstanding for Company employees during the period from December 31, 2019 to December 31, 2020 are presented in the following table: Options Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (Millions of Dollars) Outstanding at December 31, 2019 392,300 68.52 Granted 79,200 105.57 Exercised (148,800) 64.21 Outstanding at December 31, 2020 322,700 $ 79.60 4.6 $ 16.5 Exercisable at December 31, 2020 110,700 $ 66.91 3.3 $ 7.1
Summary of Additional Stock Option Information	Additional information about stock options outstanding at December 31, 2020 is shown below: Options Outstanding Options Exercisable Range of Exercise Prices per Option No. of Options Avg. Life Remaining in Years No. of Options Avg. Life Remaining in Years $50.00 to $59.99 7,300 2.1 7,300 2.1 $60.00 to $69.99 69,500 3.1 69,500 3.1 $70.00 to $79.99 166,700 4.6 33,900 3.9 $80.00 to $89.99 3,600 6.2 — $100.00 to $109.99 75,600 6.1 — 322,700 4.6 110,700 3.3
Summary of Restricted Stock Unit Activity	Changes in restricted stock units outstanding for Company employees during the period from December 31, 2019 to December 31, 2020 are presented in the following table: Employee RSUs Number of units Weighted Average Grant Date Fair Value Total Fair Value (Millions of Dollars) Outstanding at December 31, 2019 198,915 $ 70.58 Granted 55,734 $ 90.09 Vested and issued (59,324) $ 66.31 $ 6.4 Forfeited (12,530) $ 78.43 Outstanding at December 31, 2020 182,795 $ 77.38 $ 23.9 Changes in performance-based restricted stock units outstanding for Company employees during the period from December 31, 2019 to December 31, 2020 are presented in the following table: Employee PSU's Number of Units Weighted Average Grant Date Fair Value Total Fair Value (Millions of Dollars) Outstanding at December 31, 2019 131,200 $ 82.98 Granted 64,290 $ 122.95 Vested and issued (65,745) $ 85.04 $ 7.0 Forfeited (405) $ 65.75 Outstanding at December 31, 2020 129,340 $ 97.01 $ 16.9 Changes in restricted stock units outstanding for Company non-employee directors during the period from December 31, 2019 to December 31, 2020 are presented in the following table: Director RSU's Number of Units Weighted Average Grant Date Fair Value Total Fair Value (Millions of Dollars) Outstanding at December 31, 2019 33,607 $ 70.68 Granted 9,801 $ 105.33 Vested and issued (12,404) $ 66.01 $ 1.3 Outstanding at December 31, 2020 31,004 $ 83.31 $ 4.1

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
Earnings Per Share (Tables)	Dec. 31, 2020
Earnings Per Share [Abstract]
Reconciliation of Basic and Diluted Earnings Per Share Computations	The following table provides a reconciliation of basic and diluted earnings per share computations for the years ended December 31, 2020, 2019 and 2018 (in millions, except per share amounts): Years ended December 31, (Millions of dollars except per share amounts) 2020 2019 2018 Earnings per common share: Net income per share - basic Net income attributable to common stockholders $ 386.1 $ 154.8 $ 213.6 Weighted average common shares outstanding (in thousands) 29,132 31,594 32,674 Earnings per common share $ 13.25 $ 4.90 $ 6.54 Earnings per common share - assuming dilution: Net income per share - diluted Net income attributable to common stockholders $ 386.1 $ 154.8 $ 213.6 Weighted average common shares outstanding (in thousands) 29,132 31,594 32,674 Common equivalent shares: Share-based awards 394 264 309 Weighted average common shares outstanding - assuming dilution (in thousands) 29,526 31,858 32,983 Earnings per common share assuming dilution $ 13.08 $ 4.86 $ 6.48
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	We have excluded from the earnings-per-share calculation certain stock options and shares that are considered to be anti-dilutive under the treasury stock method and are reported in the table below. Years ended December 31, Potentially dilutive shares excluded from the calculation as their inclusion would be anti-dilutive 2020 2019 2018 Stock options 75,600 94,600 76,400 Restricted share units 20,137 843 121 Total anti-dilutive shares 95,737 95,443 76,521

Other Financial Information (Ta

Other Financial Information (Tables)	12 Months Ended
Other Financial Information (Tables)	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary of Changes in Operating Working Capital	CHANGES IN WORKING CAPITAL - Years ended December 31, (Millions of dollars) 2020 2019 2018 Accounts receivable $ 4.9 $ (33.4) $ 86.6 Inventories (51.7) (6.1) (39.0) Prepaid expenses and other current assets 16.6 (3.3) 11.4 Accounts payable and accrued liabilities 8.3 (5.9) (56.7) Income taxes payable 8.8 — — Net decrease (increase) in noncash operating working capital $ (13.1) $ (48.7) $ 2.3

Assets and Liabilities Measur_2

Assets and Liabilities Measure at Fair Value (Tables)	12 Months Ended
Assets and Liabilities Measure at Fair Value (Tables)	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Schedule of Carrying Amounts and Estimated Fair Value of Financial Instruments	The following table presents the carrying amounts and estimated fair values of financial instruments held by the Company at December 31, 2020 and 2019. The fair value of a financial instrument is the amount at which the instrument could be exchanged in a current transaction between willing parties. The table excludes Cash and cash equivalents, Accounts receivable-trade, and Trade accounts payable and accrued liabilities, all of which had fair values approximating carrying amounts. The fair value of Current and Long-term debt was estimated based on rates offered to the Company at that time for debt of the same maturities. The Company has off-balance sheet exposures relating to certain financial guarantees and letters of credit. The fair value of these, which represents fees associated with obtaining the instruments, was nominal. December 31, 2020 December 31, 2019 Carrying Carrying (Millions of dollars) Amount Fair Value Amount Fair Value Financial liabilities Current and long-term debt $ (1,002.4) $ (1,029.9) $ (1,038.1) $ (1,069.4)

Leases (Tables)

Leases (Tables)	12 Months Ended
Leases (Tables)	Dec. 31, 2020
Leases [Abstract]
Lessee, Lease	Leases are reflected in the following balance sheet accounts: (Millions of dollars) Classification December 31, December 31, Assets Operating (Right-of-use) Other Assets $ 147.7 $ 124.2 Finance Property, plant, and equipment, at cost, less accumulated depreciation of $2.8 in 2020 and $2.2 in 2019 2.6 3.0 Total leased assets $ 150.3 $ 127.2 (Millions of dollars) Classification December 31, December 31, Liabilities Current Operating Trade accounts payable and accrued liabilities $ 7.8 $ 6.8 Finance Current maturities of long-term debt 1.2 1.2 Noncurrent Operating Deferred credits and other liabilities 142.5 118.5 Finance Long-term debt, including capitalized lease obligations 0.9 1.2 Total lease liabilities $ 152.4 $ 127.7
Lease, Cost	Lease Cost: Year Ended December 31, (Millions of dollars) Classification 2020 2019 Operating lease cost Station and other operating expenses $ 16.6 $ 14.5 Finance lease cost Amortization of leased assets Depreciation & amortization expense 1.3 1.2 Interest on lease liabilities Interest expense 0.1 0.1 Net lease costs $ 18.0 $ 15.8 Cash flow information: Year Ended December 31, (Millions of dollars) 2020 2019 Cash paid for amounts included in the measurement of liabilities Operating cash flows required by operating leases $ 15.5 $ 13.8 Operating cash flows required by finance leases $ 0.1 $ 0.1 Financing cash flows required by finance leases $ 1.4 $ 1.4 Lease Term and Discount Rate: Year Ended December 31, 2020 Weighted average remaining lease term (years) Finance leases 2.0 Operating leases 15.7 Weighted average discount rate Finance leases 4.2 % Operating leases 5.7 %
Maturity of Operating Lease Liability	Maturity of Lease Liabilities: (Millions of dollars) Operating leases Finance leases 2021 $ 16.8 $ 1.2 2022 15.9 0.7 2023 15.4 0.3 2024 14.9 — 2025 14.2 — After 2025 166.9 — Total lease payments 244.1 2.2 less: interest 93.8 0.1 Present value of lease liabilities $ 150.3 $ 2.1
Maturity of Finance Lease Liabilities	Maturity of Lease Liabilities: (Millions of dollars) Operating leases Finance leases 2021 $ 16.8 $ 1.2 2022 15.9 0.7 2023 15.4 0.3 2024 14.9 — 2025 14.2 — After 2025 166.9 — Total lease payments 244.1 2.2 less: interest 93.8 0.1 Present value of lease liabilities $ 150.3 $ 2.1

Business Segments (Tables)

Business Segments (Tables)	12 Months Ended
Business Segments (Tables)	Dec. 31, 2020
Segment Reporting [Abstract]
Summary of Information by Business Segment	Segment Information Corporate and Other Assets (Millions of dollars) Marketing Consolidated Year ended December 31, 2020 Segment income (loss) $ 442.2 $ (56.1) $ 386.1 Revenues from external customers $ 11,264.0 $ 0.3 $ 11,264.3 Interest income $ — $ 1.0 $ 1.0 Interest expense $ (0.1) $ (51.1) $ (51.2) Loss on early debt extinguishment $ — $ — $ — Income tax expense (benefit) $ 132.9 $ (9.9) $ 123.0 Significant noncash charges (credits) Depreciation and amortization $ 146.3 $ 14.7 $ 161.0 Accretion of asset retirement obligations $ 2.3 $ — $ 2.3 Debt extinguishment costs $ — $ — $ — Deferred and noncurrent income taxes (benefits) $ 2.8 $ (0.3) $ 2.5 Additions to property, plant and equipment $ 200.8 $ 26.3 $ 227.1 Total assets at year-end $ 2,418.2 $ 267.5 $ 2,685.7 Segment Information Corporate and Other Assets (Millions of dollars) Marketing Consolidated Year ended December 31, 2019 Segment income (loss) $ 215.0 $ (60.2) $ 154.8 Revenues from external customers $ 14,034.3 $ 0.3 $ 14,034.6 Interest income $ — $ 3.2 $ 3.2 Interest expense $ (0.1) $ (54.8) $ (54.9) Loss on early debt extinguishment $ — $ (14.8) $ (14.8) Income tax expense (benefit) $ 66.3 $ (18.7) $ 47.6 Significant noncash charges (credits) Depreciation and amortization $ 138.9 $ 13.3 $ 152.2 Accretion of asset retirement obligations $ 2.1 $ — $ 2.1 Debt extinguishment costs $ — $ 4.4 $ 4.4 Deferred and noncurrent income taxes (benefits) $ 32.9 $ (9.2) $ 23.7 Additions to property, plant and equipment $ 155.5 $ 59.1 $ 214.6 Total assets at year-end $ 2,304.7 $ 382.5 $ 2,687.2 Segment Information Corporate and Other Assets (Millions of dollars) Marketing Consolidated Year ended December 31, 2018 Segment income (loss) $ 214.2 $ (0.6) $ 213.6 Revenues from external customers $ 14,362.3 $ 0.6 $ 14,362.9 Interest income $ — $ 1.5 $ 1.5 Interest expense $ (0.1) $ (52.8) $ (52.9) Income tax expense (benefit) $ 69.5 $ (9.2) $ 60.3 Significant noncash charges (credits) Depreciation and amortization $ 124.5 $ 9.5 $ 134.0 Accretion of asset retirement obligations $ 2.0 $ — $ 2.0 Deferred and noncurrent income taxes (benefits) $ 39.0 $ (1.1) $ 37.9 Additions to property, plant and equipment $ 169.2 $ 24.6 $ 193.8 Total assets at year-end $ 2,012.0 $ 348.8 $ 2,360.8

Description of Business and B_2

Description of Business and Basis of Presentation (Details)	Aug. 31, 2013	Aug. 30, 2013	Dec. 31, 2020storesstates
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Percentage of shares of stock distributed		100.00%
Ownership interest after transaction (percent)	0.00%
Number of states in which entity operates \| states			25
Number of stores \| stores			1,503

Significant Accounting Polici_3

Significant Accounting Policies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Excise taxes	$ 1,760	$ 1,933.3	$ 1,838.9
Interest costs capitalized	$ 1.4	$ 1.4	$ 2.2
LKE transaction, required term to facilitate forward agreement before proceeds are reclassified as available cash (in days)	180 days
Pipeline and terminal facilities \| Minimum
Property, Plant and Equipment [Line Items]
Depreciable life (in years)	16 years
Pipeline and terminal facilities \| Maximum
Property, Plant and Equipment [Line Items]
Depreciable life (in years)	25 years
Retail gasoline stations \| Minimum
Property, Plant and Equipment [Line Items]
Depreciable life (in years)	3 years
Retail gasoline stations \| Maximum
Property, Plant and Equipment [Line Items]
Depreciable life (in years)	50 years
Nonqualified Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)	3 years
Restricted Stock And Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)	3 years

Revenues (Disaggregation of Rev

Revenues (Disaggregation of Revenue) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Revenue	$ 11,264.3	$ 14,034.6	$ 14,362.9
Merchandise sales
Disaggregation of Revenue [Line Items]
Revenue	2,955.1	2,620.1	2,423
Operating Segment \| Marketing
Disaggregation of Revenue [Line Items]
Revenue	11,264	14,034.3	14,362.3
Operating Segment \| Marketing \| Total petroleum product sales
Disaggregation of Revenue [Line Items]
Revenue	8,208.6	11,373.8	11,858.4
Operating Segment \| Marketing \| Petroleum product sales (at retail)
Disaggregation of Revenue [Line Items]
Revenue	7,444.6	10,184	10,459.2
Operating Segment \| Marketing \| Petroleum product sales (at wholesale)
Disaggregation of Revenue [Line Items]
Revenue	764	1,189.8	1,399.2
Operating Segment \| Marketing \| Merchandise sales
Disaggregation of Revenue [Line Items]
Revenue	2,955.1	2,620.1	2,423
Operating Segment \| Marketing \| RINs
Disaggregation of Revenue [Line Items]
Revenue	95.5	34.8	75.2
Operating Segment \| Marketing \| Other
Disaggregation of Revenue [Line Items]
Revenue	4.8	5.6	5.7
Corporate and Other Assets
Disaggregation of Revenue [Line Items]
Revenue	$ 0.3	$ 0.3	$ 0.6

Revenues (Narrative) (Details)

Revenues (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
Revenues (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Earned rewards, expiration period	90 days
Trade accounts receivable	$ 168.8	$ 172.9
Receivables related to contracts with customers
Disaggregation of Revenue [Line Items]
Trade accounts receivable	$ 88.3	$ 96
Petroleum product sales, rack sales
Disaggregation of Revenue [Line Items]
Collection period	10 days
Renewable Identification Numbers (RINs) sales
Disaggregation of Revenue [Line Items]
Collection period	5 days
Minimum \| Petroleum product sales (at retail)
Disaggregation of Revenue [Line Items]
Collection period	2 days
Maximum \| Petroleum product sales (at retail)
Disaggregation of Revenue [Line Items]
Collection period	7 days

Inventories (Summary Of Invento

Inventories (Summary Of Inventory) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Inventory Disclosure [Abstract]
Finished products - FIFO basis	$ 223	$ 259.2
Less LIFO reserve - finished products	(101.3)	(160.8)
Finished products - LIFO basis	121.7	98.4
Store merchandise for resale	152	123
Materials and supplies	5.4	6.2
Total inventories	279.1	227.6
LIFO carrying reserve	$ 101.3	$ 160.8

Property, Plant and Equipment_2

Property, Plant and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Cost	$ 3,059	$ 2,886.5
Net	1,867.6	1,807.3
Depreciation expense	160	151.2	$ 132.5
Land
Property, Plant and Equipment [Line Items]
Cost	609.5	598.6
Net	609.5	598.6
Pipeline and terminal facilities
Property, Plant and Equipment [Line Items]
Cost	79.8	77.5
Net	43.5	43.7
Retail gasoline stations
Property, Plant and Equipment [Line Items]
Cost	2,179.7	2,034.4
Net	1,123.2	1,073.6
Buildings
Property, Plant and Equipment [Line Items]
Cost	66.7	60.5
Net	48.5	44.9
Other
Property, Plant and Equipment [Line Items]
Cost	123.3	115.5
Net	$ 42.9	$ 46.5
Minimum \| Pipeline and terminal facilities
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	16 years
Minimum \| Retail gasoline stations
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	3 years
Minimum \| Buildings
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	20 years
Minimum \| Other
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	3 years
Maximum \| Pipeline and terminal facilities
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	25 years
Maximum \| Retail gasoline stations
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	50 years
Maximum \| Buildings
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	45 years
Maximum \| Other
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	20 years

Accounts Payable And Accrued _3

Accounts Payable And Accrued Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Payables and Accruals [Abstract]
Trade accounts payable	$ 261	$ 280.8
Excise taxes/withholdings payable	84.1	86.2
Accrued insurance obligations	30.3	24.4
Accrued taxes other than income	31.7	25.6
Accrued compensation and benefits	32.5	26.5
Other	31.5	22.7
Accounts payable and accrued liabilities	$ 471.1	$ 466.2

Long-Term Debt (Summary of Long

Long-Term Debt (Summary of Long-Term Debt) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Sep. 13, 2019	Apr. 25, 2017
Debt Instrument [Line Items]
Capitalized lease obligations, vehicles, due through 2024	$ 2.1	$ 2.4
Unamortized debt issuance costs	(4.4)	(5.5)
Total long-term debt	1,002.4	1,038.1
Less current maturities	51.2	38.8
Total long-term debt, net of current	951.2	999.3
Senior Notes \| 5.625% senior notes due 2027 (net of unamortized discount of $2.4 at 2020 and $2.7 at 2019)
Debt Instrument [Line Items]
Long-term debt	297.6	297.3
Interest rate (percent)				5.625%
Unamortized discount	2.4	2.7
Senior Notes \| 4.75% senior notes due 2029 (net of unamortized discount of $5.4 at 2020 and $6.1 at 2019)
Debt Instrument [Line Items]
Long-term debt	494.6	493.9
Interest rate (percent)			4.75%
Unamortized discount	5.4	6.1
Secured Debt \| Term loan due 2023 (effective interest rate of 2.67% at 2020 and 4.31% at 2019)
Debt Instrument [Line Items]
Long-term debt	$ 212.5	$ 250
Effective interest rate	2.67%	4.31%

Long-Term Debt (Narrative) (Det

Long-Term Debt (Narrative) (Details) - USD ($)	Apr. 01, 2020	Aug. 27, 2019	Dec. 31, 2020	Sep. 13, 2019	Aug. 31, 2019	Apr. 25, 2017
Debt Instrument [Line Items]
Fixed charge coverage ratio			0.90
Fixed charge coverage ratio threshold, percentage of aggregate facility commitments and borrowing base			17.50%
Fixed charge coverage ratio threshold, amount of aggregate facility commitments and borrowing base			$ 70,000,000
Secured debt to EBITDA ratio			0.29
Shortfall of net income and retained earnings			$ 82,700,000
Minimum
Debt Instrument [Line Items]
Fixed charge coverage ratio			1
Period for fixed charge coverage ratio threshold (in days)			3 days
Dividend restriction threshold as amount of availability			$ 100,000,000
Dividend restriction threshold as a percentage of revolving commitments and borrowing base			25.00%
Maximum
Debt Instrument [Line Items]
Secured debt to EBITDA ratio			4.5
Dividend restriction threshold as a percentage of revolving commitments and borrowing base with consideration of fixed charge coverage ratio			40.00%
Federal Funds Rate
Debt Instrument [Line Items]
Spread over variable rate (percent)			0.50%
LIBOR
Debt Instrument [Line Items]
Spread over variable rate (percent)			1.00%
Cash
Debt Instrument [Line Items]
Percentage of asset available to borrow against			100.00%
Credit Card Receivables
Debt Instrument [Line Items]
Percentage of asset available to borrow against			90.00%
Investment Grade Accounts
Debt Instrument [Line Items]
Percentage of asset available to borrow against			90.00%
Other Accounts
Debt Instrument [Line Items]
Percentage of asset available to borrow against			85.00%
Midstream Refined Products Inventory
Debt Instrument [Line Items]
Percentage of asset available to borrow against			80.00%
Refined Retail Products Inventory
Debt Instrument [Line Items]
Percentage of asset available to borrow against			75.00%
Retail Merchandise Inventory
Debt Instrument [Line Items]
Percentage of asset available to borrow against			70.00%
Percentage of net orderly liquidation value available to borrow against			85.00%
Secured Debt
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity					$ 325,000,000
Secured Debt \| LIBOR \| Minimum
Debt Instrument [Line Items]
Spread over variable rate (percent)			1.50%
Secured Debt \| LIBOR \| Maximum
Debt Instrument [Line Items]
Spread over variable rate (percent)			2.00%
Secured Debt \| Alternative Base Rate \| Minimum
Debt Instrument [Line Items]
Spread over variable rate (percent)			0.50%
Secured Debt \| Alternative Base Rate \| Maximum
Debt Instrument [Line Items]
Spread over variable rate (percent)			1.00%
Term Loan
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity					200,000,000
Proceeds from lines of credit		$ 200,000,000
Debt instrument term		4 years
Repayments of long-term debt		$ 57,000,000
Additional term loan			$ 50,000,000
Outstanding balance			$ 212,500,000
Principal payment period	$ 12,500,000
Term Loan \| LIBOR \| Minimum
Debt Instrument [Line Items]
Spread over variable rate (percent)			2.50%
Term Loan \| LIBOR \| Maximum
Debt Instrument [Line Items]
Spread over variable rate (percent)			2.75%
Term Loan \| Alternative Base Rate \| Minimum
Debt Instrument [Line Items]
Spread over variable rate (percent)			1.50%
Term Loan \| Alternative Base Rate \| Maximum
Debt Instrument [Line Items]
Spread over variable rate (percent)			1.75%
Additional Term Loan Available Until December 2019
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity					50,000,000
Incremental Facility
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity					150,000,000
ABL Facility
Debt Instrument [Line Items]
Additional term loan			$ 100,000,000
Outstanding under facility			$ 0
Letter Of Credit
Debt Instrument [Line Items]
Line of credit facility, sublimit					$ 100,000,000
Senior Notes \| 5.625% senior notes due 2027
Debt Instrument [Line Items]
Senior notes						$ 300,000,000
Interest rate (percent)						5.625%
Senior Notes \| Senior Notes 4.75 Percent Due 2029
Debt Instrument [Line Items]
Senior notes				$ 500,000,000
Interest rate (percent)				4.75%

Asset Retirement Obligations _3

Asset Retirement Obligations (ARO) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Asset Retirement Obligation Roll Forward
Balance at beginning of period	$ 32.8	$ 30.7
Accretion expense	2.3	2.1	$ 2
Settlement of liabilities	(0.8)	(0.4)
Liabilities incurred	0.8	0.4
Balance at end of period	$ 35.1	$ 32.8	$ 30.7

Income Taxes (Schedule Of Compo

Income Taxes (Schedule Of Components Of Income From Continuing Operations Before Income Taxes And Income Tax Expense (Benefit)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income (loss) before income taxes	$ 509.1	$ 202.4	$ 273.9
Income tax expense (benefit)
Federal - Current	96	15.6	18.4
Federal - Deferred	4.7	21.7	31
State - Current and deferred	22.3	10.3	10.9
Total	$ 123	$ 47.6	$ 60.3

Income Taxes (Schedule Of Recon

Income Taxes (Schedule Of Reconciliation Of Income Taxes To Statutory Rate) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income tax expense based on the U.S. statutory tax rate	$ 106.9	$ 42.5	$ 57.5
State income taxes, net of federal benefit	17.5	8.6	8.3
Federal credits	(1.9)	(2.3)	(2)
Other, net	0.5	(1.2)	(3.5)
Total	$ 123	$ 47.6	$ 60.3

Income Taxes (Summary Of Deferr

Income Taxes (Summary Of Deferred Tax Assets And Deferred Tax Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets
Property costs and asset retirement obligations	$ 4.5	$ 3.7
Employee benefits	8	6.1
Operating leases liability	31.6	25
Other deferred tax assets	7.2	2.1
Total gross deferred tax assets	51.3	36.9
Deferred tax liabilities
Accumulated depreciation and amortization	(213.2)	(191.2)
State deferred taxes	(20.2)	(27.9)
Operating leases right of use assets	(31)	(24.8)
Other deferred tax liabilities	(5.3)	(9.7)
Total gross deferred tax liabilities	(269.7)	(253.6)
Net deferred tax liabilities	$ (218.4)	$ (216.7)

Income Taxes (Reconciliation of

Income Taxes (Reconciliation of Beginning and Ending Liability For Uncertain Tax Positions) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at January 1	$ 0.6	$ 0.7
Additions for tax positions related to prior years	0.1	0.5
Settlements with taxing authorities	(0.3)	(0.6)
Balance at December 31	$ 0.4	$ 0.6

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
Income Taxes (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Unrecognized tax benefits that would impact effective tax rate	$ 0.3	$ 0.5
Excess tax benefits	$ 2.2	$ 0.1	$ 2.5

Incentive Plans (Narrative) (De

Incentive Plans (Narrative) (Details)	12 Months Ended			76 Months Ended
Incentive Plans (Narrative) (Details)	Dec. 31, 2020USD ($)$ / sharespeerCompaniesshares	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2019shares	Feb. 12, 2014shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted (in shares)	79,200
Unrecognized compensation cost related to stock option awards \| $	$ 18,100,000
Unrecognized compensation cost related to stock option awards, weighted average period for recognition (in years)	1 year 8 months 12 days
Total income tax benefits realized from tax deductions related to stock option exercises under share-based payment arrangements \| $	$ 700,000	$ 100,000	$ 2,100,000
2013 Long-Term Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares authorized for incentive plan (in shares)					5,500,000
Maximum number of shares per employee (in shares)	1,000,000
Maximum amount payable \| $	$ 5,000,000
Shares granted (in shares)				2,491,559
Shares available for grant (in shares)	3,008,441
2013 Stock Plan For Non-Employee Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares authorized for incentive plan (in shares)	500,000
Shares available for grant (in shares)	366,570
Restricted stock units issued (in shares)				133,430
2013 Stock Plan For Non-Employee Directors \| Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units issued (in shares)	9,801
Award vesting period (in years)	3 years
Restricted stock units issued, weighted average grant date fair value (in dollars per share) \| $ / shares	$ 105.33
MUSA 2013 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units issued (in shares)	55,734
Option term (in years)	7 years
Restricted stock units issued, weighted average grant date fair value (in dollars per share) \| $ / shares	$ 90.09
MUSA 2013 Plan \| Return On Average Capital Employed Performance Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)	3 years
Restricted stock units issued, weighted average grant date fair value (in dollars per share) \| $ / shares	$ 106.72
MUSA 2013 Plan \| Total Shareholder Return Performance Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)	3 years
Number of companies in total shareholder return peer comparison group \| peerCompanies	18
Restricted stock units issued, weighted average grant date fair value (in dollars per share) \| $ / shares	$ 142.07
MUSA 2013 Plan \| Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)	3 years

Incentive Plans (Schedule of Sh

Incentive Plans (Schedule of Share-Based Plan Amounts Recognized) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Payment Arrangement [Abstract]
Compensation charged against income before income tax benefit	$ 14.3	$ 10.5	$ 9.2
Related income tax benefit recognized in income	$ 3	$ 2.2	$ 1.9

Incentive Plans (Summary of Val

Incentive Plans (Summary of Valuation Assumptions) (Details) - MUSA 2013 Plan - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value per option grant (in dollars per share)	$ 28.28	$ 20.48	$ 17.32
Dividend yield	0.00%	0.00%	0.00%
Expected volatility	28.10%	26.80%	27.00%
Risk-free interest rate	1.50%	2.50%	2.40%
Expected life (in years)	4 years 8 months 12 days	4 years 6 months	3 years 10 months 24 days
Stock price at valuation date (usd per share)	$ 106.72	$ 76.15	$ 71

Incentive Plans (Summary of Cha

Incentive Plans (Summary of Changes in Stock Options Outstanding) (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)$ / sharesshares
Number of Shares (in shares)
Beginning balance (in shares) \| shares	392,300
Granted (in shares) \| shares	79,200
Exercised (in shares) \| shares	(148,800)
Ending balance (in shares) \| shares	322,700
Exercisable (in shares) \| shares	110,700
Average Exercise Price (in dollars per share)
Beginning balance (in dollars per share) \| $ / shares	$ 68.52
Granted (in dollars per share) \| $ / shares	105.57
Exercised (in dollars per share) \| $ / shares	64.21
Ending balance (in dollars per share) \| $ / shares	79.60
Shares exercisable, average exercise price (in dollars per share) \| $ / shares	$ 66.91
Options outstanding, average remaining life (in years)	4 years 7 months 6 days
Options exercisable, average remaining life (in years)	3 years 3 months 18 days
Outstanding, aggregate intrinsic value \| $	$ 16.5
Options exercisable, aggregate intrinsic value \| $	$ 7.1

Incentive Plans (Summary of Add

Incentive Plans (Summary of Additional Stock Option Information) (Details)	12 Months Ended
	Dec. 31, 2020$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding (in shares)	322,700
Options outstanding, average remaining life (in years)	4 years 7 months 6 days
Options exercisable (in shares)	110,700
Options exercisable, average remaining life (in years)	3 years 3 months 18 days
$50.00 to $59.99
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Lower range limit of exercise price (in dollars per share) \| $ / shares	$ 50
Upper range limit of exercise price (in dollars per share) \| $ / shares	$ 59.99
Options outstanding (in shares)	7,300
Options outstanding, average remaining life (in years)	2 years 1 month 6 days
Options exercisable (in shares)	7,300
Options exercisable, average remaining life (in years)	2 years 1 month 6 days
$60.00 to $69.99
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Lower range limit of exercise price (in dollars per share) \| $ / shares	$ 60
Upper range limit of exercise price (in dollars per share) \| $ / shares	$ 69.99
Options outstanding (in shares)	69,500
Options outstanding, average remaining life (in years)	3 years 1 month 6 days
Options exercisable (in shares)	69,500
Options exercisable, average remaining life (in years)	3 years 1 month 6 days
$70.00 to $79.99
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Lower range limit of exercise price (in dollars per share) \| $ / shares	$ 70
Upper range limit of exercise price (in dollars per share) \| $ / shares	$ 79.99
Options outstanding (in shares)	166,700
Options outstanding, average remaining life (in years)	4 years 7 months 6 days
Options exercisable (in shares)	33,900
Options exercisable, average remaining life (in years)	3 years 10 months 24 days
$80.00 to $89.99
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Lower range limit of exercise price (in dollars per share) \| $ / shares	$ 80
Upper range limit of exercise price (in dollars per share) \| $ / shares	$ 89.99
Options outstanding (in shares)	3,600
Options outstanding, average remaining life (in years)	6 years 2 months 12 days
Options exercisable (in shares)	0
Options exercisable, average remaining life (in years)
$100.00 to $109.99
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Lower range limit of exercise price (in dollars per share) \| $ / shares	$ 100
Upper range limit of exercise price (in dollars per share) \| $ / shares	$ 109.99
Options outstanding (in shares)	75,600
Options outstanding, average remaining life (in years)	6 years 1 month 6 days
Options exercisable (in shares)	0
Options exercisable, average remaining life (in years)

Incentive Plans (Summary of Res

Incentive Plans (Summary of Restricted Stock Unit Activity) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended	76 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
MUSA 2013 Plan
Number of units
Beginning balance (in shares)	198,915
Granted (in shares)	55,734
Vested and issued (in shares)	(59,324)
Forfeited (in shares)	(12,530)
Ending balance (in shares)	182,795	198,915
Weighted Average Grant Date Fair Value (in dollars per share)
Beginning balance (in dollars per share)	$ 70.58
Granted (in dollars per share)	90.09
Vested and issued (in dollars per share)	66.31
Forfeited (in dollars per share)	78.43
Ending balance (in dollars per share)	$ 77.38	$ 70.58
Total fair value vested	$ 6.4
Total fair value,outstanding	$ 23.9
MUSA 2013 Plan \| Performance Units
Number of units
Beginning balance (in shares)	131,200
Granted (in shares)	64,290
Vested and issued (in shares)	(65,745)
Forfeited (in shares)	(405)
Ending balance (in shares)	129,340	131,200
Weighted Average Grant Date Fair Value (in dollars per share)
Beginning balance (in dollars per share)	$ 82.98
Granted (in dollars per share)	122.95
Vested and issued (in dollars per share)	85.04
Forfeited (in dollars per share)	65.75
Ending balance (in dollars per share)	$ 97.01	$ 82.98
Total fair value vested	$ 7
Total fair value,outstanding	$ 16.9
2013 Stock Plan For Non-Employee Directors
Number of units
Granted (in shares)		133,430
2013 Stock Plan For Non-Employee Directors \| Restricted Stock Units
Number of units
Beginning balance (in shares)	33,607
Granted (in shares)	9,801
Vested and issued (in shares)	(12,404)
Ending balance (in shares)	31,004	33,607
Weighted Average Grant Date Fair Value (in dollars per share)
Beginning balance (in dollars per share)	$ 70.68
Granted (in dollars per share)	105.33
Vested and issued (in dollars per share)	66.01
Ending balance (in dollars per share)	$ 83.31	$ 70.68
Total fair value vested	$ 1.3
Total fair value,outstanding	$ 4.1

Employee and Retiree Benefit _2

Employee and Retiree Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Supplemental Executive Retirement Plan
Defined Contribution Plan Disclosure [Line Items]
Liability for retirement plan	$ 3.7	$ 2.1
Profit Sharing Plan
Defined Contribution Plan Disclosure [Line Items]
Profit sharing contributions	$ 1.8	1.5	$ (0.8)
Thrift Plan
Defined Contribution Plan Disclosure [Line Items]
Company matching contribution (percent)	100.00%
Employee's maximum contribution matched by Company (percent)	6.00%
Profit sharing percentage 1	5.00%
Profit sharing percentage 2	7.00%
Profit sharing percentage 3	9.00%
Profit sharing contributions	$ 15.3	$ 12.9	$ 9.7

Financial Instruments and Ris_2

Financial Instruments and Risk Management (Details) - USD ($) $ in Millions	Sep. 27, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Aug. 27, 2019
Derivatives, Fair Value [Line Items]
Cash deposits related to commodity derivative contracts		$ 0.6	$ 1
Realized loss (gain) on derivative		(0.9)
Remaining pre-tax income (loss) deferred on derivative contracts		(3.4)	1	$ 0
Income tax (benefit) on derivative contracts		(0.8)	0.2	$ 0
Interest Rate Swap
Derivatives, Fair Value [Line Items]
Notional amount		127.5			$ 150
Quarterly decrease in derivative balance	$ 7.5
Realized loss (gain) on derivative			0.2
Remaining pre-tax income (loss) deferred on derivative contracts		(3.4)	0.9
Income tax (benefit) on derivative contracts		$ (0.8)	$ 0.2

Earnings Per Share (Narrative)

Earnings Per Share (Narrative) (Details) - USD ($)	Jul. 24, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Oct. 28, 2020
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, shares acquired (in shares)		3,338,028	1,898,023	1,994,632
Common stock acquired		$ 399,600,000	$ 165,800,000	$ 144,400,000
Stock repurchase program, average price per share (in dollars per share)		$ 119.70	$ 87.35	$ 72.39
July 2019 Share Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, authorized amount	$ 400,000,000
Stock repurchase program period	2 years
Stock repurchase program, shares acquired (in shares)		2,368,374	1,393,626
Common stock acquired		$ 274,600,000	$ 125,000,000
Stock repurchase program, average price per share (in dollars per share)		$ 115.93	$ 89.70
October 2020 Share Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, authorized amount					$ 500,000,000
Stock repurchase program, shares acquired (in shares)		969,654
Common stock acquired		$ 125,000,000
Stock repurchase program, average price per share (in dollars per share)		$ 128.91
Stock repurchase program, remaining amount	$ 375,000,000
Other Share Repurchase Programs
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, shares acquired (in shares)			504,397
Common stock acquired			$ 40,800,000
Stock repurchase program, average price per share (in dollars per share)			$ 80.85

Earnings Per Share (Reconciliat

Earnings Per Share (Reconciliation of Basic and Diluted Earnings Per Share Computations) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings per common share:
Net income	$ 386.1	$ 154.8	$ 213.6
Weighted average common shares outstanding (in thousands) (in shares)	29,132	31,594	32,674
Earnings per common share (in dollars per share)	$ 13.25	$ 4.90	$ 6.54
Earnings per common share - assuming dilution:
Net income	$ 386.1	$ 154.8	$ 213.6
Weighted average common shares outstanding (in thousands) (in shares)	29,132	31,594	32,674
Common equivalent shares:
Share-based awards (in shares)	394	264	309
Weighted average common shares outstanding - assuming dilution (in thousands) (in shares)	29,526	31,858	32,983
Earnings per common share assuming dilution (in dollars per share)	$ 13.08	$ 4.86	$ 6.48

Earnings Per Share (Potentially

Earnings Per Share (Potentially Dilutive Shares Excluded from Earnings Per Share) (Details) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	95,737	95,443	76,521
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	75,600	94,600	76,400
Restricted share units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	20,137	843	121

Other Financial Information (Na

Other Financial Information (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Income taxes paid (collected), net	$ 96.5	$ 26.9	$ 17.4
Interest paid, net of amounts capitalized	$ 49.1	$ 56.6	$ 50.4

Other Financial Information (Su

Other Financial Information (Summary Of Changes In Operating Working Capital) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accounts receivable	$ 4.9	$ (33.4)	$ 86.6
Inventories	(51.7)	(6.1)	(39)
Prepaid expenses and other current assets	16.6	(3.3)	11.4
Accounts payable and accrued liabilities	8.3	(5.9)	(56.7)
Income taxes payable	8.8	0	0
Net decrease (increase) in noncash operating working capital	$ (13.1)	$ (48.7)	$ 2.3

Assets and Liabilities Measur_3

Assets and Liabilities Measure at Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current and long-term debt	$ (1,002.4)	$ (1,038.1)
Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current and long-term debt	$ (1,029.9)	$ (1,069.4)

Commitments (Details)

Commitments (Details) - USD ($) $ in Millions	12 Months Ended
Commitments (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating leases
2021	$ 16.8
2022	15.9
2023	15.4
2024	14.9
2025	14.2
Rental expense for noncancelable operating leases	$ 24.9	$ 21.6
Rental expense for noncancelable operating leases			$ 15.2
Take-Or-Pay Contracts
Other Commitments [Line Items]
Term of take-or-pay contract	9 years 9 months 18 days
Minimum annual payments under take-or-pay contracts, fiscal year maturity
2021	$ 9.1
2022	4
2023	4
2024	4
2025	4
Capital Addition Purchase Commitments
Other Commitments [Line Items]
Commitments for capital expenditures	286.8
Construction in Progress
Other Commitments [Line Items]
Commitments for capital expenditures	278.3
Building Improvements
Other Commitments [Line Items]
Commitments for capital expenditures	$ 4.1

Contingencies (Details)

Contingencies (Details) $ in Millions	12 Months Ended
Contingencies (Details) $ in Millions	Dec. 31, 2020USD ($)superfundSites
Commitments and Contingencies Disclosure [Abstract]
Number of Superfund sites for which company may be liable \| superfundSites	1
Workers' compensation deductible (per occurrence)	$ 1
General liability insurance deductible	3
Auto liability insurance deductible	0.3
Workers' compensation accrued liability	27.8
Outstanding letters of credit	$ 13

Leases (Narrative) (Details)

Leases (Narrative) (Details)	12 Months Ended
Leases (Narrative) (Details)	Dec. 31, 2020contractsuperfundSites
Lessee, Lease, Description [Line Items]
Number of leases with restrictive covenants \| superfundSites	102
Minimum
Lessee, Lease, Description [Line Items]
Remaining lease term	1 year
Lease renewal term	5 years
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease term	20 years
Lease renewal term	20 years
Land
Lessee, Lease, Description [Line Items]
Number of leases	232
Terminal
Lessee, Lease, Description [Line Items]
Number of leases	1

Leases (Leases Reflected on Bal

Leases (Leases Reflected on Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Assets
Operating leases right of use assets	$ 147.7	$ 124.2
Finance	2.6	3
Total leased assets	150.3	127.2
Accumulated depreciation	2.8	2.2
Current
Operating	7.8	6.8
Finance	1.2	1.2
Noncurrent
Operating	142.5	118.5
Finance	0.9	1.2
Total lease liabilities	$ 152.4	$ 127.7
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:OtherAssetsNoncurrent
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:AccountsPayableAndAccruedLiabilitiesCurrent	us-gaap:AccountsPayableAndAccruedLiabilitiesCurrent
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:LongTermDebtAndCapitalLeaseObligationsCurrent
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:DeferredCreditsAndOtherLiabilities	us-gaap:DeferredCreditsAndOtherLiabilities
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:LongTermDebtAndCapitalLeaseObligations	us-gaap:LongTermDebtAndCapitalLeaseObligations

Leases (Lease Cost) (Details)

Leases (Lease Cost) (Details) - USD ($) $ in Millions	12 Months Ended
Leases (Lease Cost) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating lease cost	$ 16.6	$ 14.5
Finance lease cost
Amortization of leased assets	1.3	1.2
Interest on lease liabilities	0.1	0.1
Net lease costs	$ 18	$ 15.8

Leases (Cash Flow Information)

Leases (Cash Flow Information) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Cash paid for amounts included in the measurement of liabilities
Operating cash flows required by operating leases	$ 15.5	$ 13.8
Operating cash flows required by finance leases	0.1	0.1
Financing cash flows required by finance leases	$ 1.4	$ 1.4

Leases (Maturity of Lease Liabi

Leases (Maturity of Lease Liability) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Operating leases
2021	$ 16.8
2022	15.9
2023	15.4
2024	14.9
2025	14.2
After 2025	166.9
Total lease payments	244.1
less: interest	93.8
Present value of lease liabilities	150.3
Finance leases
2021	1.2
2022	0.7
2023	0.3
2024	0
2025	0
After 2025	0
Total lease payments	2.2
less: interest	0.1
Present value of lease liabilities	$ 2.1	$ 2.4

Leases (Lease Term and Discount

Leases (Lease Term and Discount Rate) (Details)	Dec. 31, 2020
Weighted average remaining lease term (years)
Finance leases	2 years
Operating leases	15 years 8 months 12 days
Weighted average discount rate
Finance leases	4.20%
Operating leases	5.70%

Recent Accounting and Reporti_2

Recent Accounting and Reporting Rules (Details) $ in Millions	Jan. 01, 2020USD ($)
Accounting Standards Update 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Impact of adoption to allowance for credit loss	$ 1.1

Business Segments (Summary of I

Business Segments (Summary of Information by Business Segment) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)segment	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Segment Reporting [Abstract]
Number of operating segments \| segment	1
Segment Reporting Information [Line Items]
Segment income (loss)	$ 386,100	$ 154,800	$ 213,600
Revenues from external customers	11,264,300	14,034,600	14,362,900
Interest income	1,000	3,200	1,500
Interest expense	(51,200)	(54,900)	(52,900)
Loss on early debt extinguishment	0	(14,800)	0
Income tax expense (benefit)	123,000	47,600	60,300
Significant noncash charges (credits)
Depreciation and amortization	161,000	152,200	134,000
Accretion of asset retirement obligations	2,300	2,100	2,000
Debt extinguishment costs	0	4,400
Deferred and noncurrent income taxes (benefits)	2,500	23,700	37,900
Additions to property, plant and equipment	227,100	214,600	193,800
Total assets at year-end	2,685,700	2,687,200	2,360,800
Operating Segment \| Marketing
Segment Reporting Information [Line Items]
Segment income (loss)	442,200	215,000	214,200
Revenues from external customers	11,264,000	14,034,300	14,362,300
Interest income	0	0	0
Interest expense	(100)	(100)	(100)
Loss on early debt extinguishment	0	0
Income tax expense (benefit)	132,900	66,300	69,500
Significant noncash charges (credits)
Depreciation and amortization	146,300	138,900	124,500
Accretion of asset retirement obligations	2,300	2,100	2,000
Debt extinguishment costs	0	0
Deferred and noncurrent income taxes (benefits)	2,800	32,900	39,000
Additions to property, plant and equipment	200,800	155,500	169,200
Total assets at year-end	2,418,200	2,304,700	2,012,000
Corporate and Other Assets
Segment Reporting Information [Line Items]
Segment income (loss)	(56,100)	(60,200)	(600)
Revenues from external customers	300	300	600
Interest income	1,000	3,200	1,500
Interest expense	(51,100)	(54,800)	(52,800)
Loss on early debt extinguishment	0	(14,800)
Income tax expense (benefit)	(9,900)	(18,700)	(9,200)
Significant noncash charges (credits)
Depreciation and amortization	14,700	13,300	9,500
Accretion of asset retirement obligations	0	0	0
Debt extinguishment costs	0	4,400
Deferred and noncurrent income taxes (benefits)	(300)	(9,200)	(1,100)
Additions to property, plant and equipment	26,300	59,100	24,600
Total assets at year-end	$ 267,500	$ 382,500	$ 348,800

Subsequent Event (Details)

Subsequent Event (Details) - USD ($)	Jan. 29, 2021	Dec. 31, 2020
LIBOR
Subsequent Event [Line Items]
Spread over variable rate (percent)		1.00%
Subsequent Event \| QuickChek
Subsequent Event [Line Items]
Percentage of equity interest acquired	100.00%
All-cash consideration paid	$ 645,000,000
Subsequent Event \| Secured Debt
Subsequent Event [Line Items]
Face amount of debt	$ 400,000,000
Debt instrument term	7 years
Proceeds from Issuance of Secured Debt	$ 400,000,000
Subsequent Event \| Secured Debt \| LIBOR
Subsequent Event [Line Items]
Spread over variable rate (percent)	1.75%
Subsequent Event \| Secured Debt \| LIBOR \| Minimum
Subsequent Event [Line Items]
Spread over variable rate (percent)	0.50%
Subsequent Event \| Senior Notes \| Senior Notes 3.750 Percent Due 2031
Subsequent Event [Line Items]
Face amount of debt	$ 500,000,000
Interest rate (percent)	3.75%
Subsequent Event \| Revolving Credit Facility
Subsequent Event [Line Items]
Line of credit facility, maximum borrowing capacity	$ 350,000,000
Debt instrument term	5 years
Subsequent Event \| Revolving Credit Facility \| LIBOR \| Minimum
Subsequent Event [Line Items]
Spread over variable rate (percent)	1.75%
Subsequent Event \| Revolving Credit Facility \| LIBOR \| Maximum
Subsequent Event [Line Items]
Spread over variable rate (percent)	2.25%

Schedule II - Valuation And Q_2

Schedule II - Valuation And Qualifying Accounts (Details) - Allowance for doubtful accounts - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at January 1,	$ 1.2	$ 1.1	$ 1.1
Charged to Expense	0	0.1	0.5
Deductions	(1.1)		(0.5)
Balance at December 31,	$ 0.1	$ 1.2	$ 1.1