Murphy USA (MUSA) 10-K 19 Feb 19 2018 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Jan. 31, 2019	Jun. 30, 2018
Document And Entity Information [Abstract]
Entity Registrant Name	Murphy USA Inc.
Trading Symbol	MUSA
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Entity Central Index Key	1,573,516
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Company	false
Entity Shell Company	false
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Entity Well-Known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Common Stock, Shares Outstanding		32,261,729
Entity Public Float			$ 2,390,188

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current assets
Cash and cash equivalents	$ 184,500	$ 170,000	$ 153,800	$ 33,700
Accounts receivable—trade, less allowance for doubtful accounts of $1.1 in 2018 and 2017	138,800	225,200
Inventories, at lower of cost or market	221,500	182,500
Prepaid expenses and other current assets	25,300	36,500
Total current assets	570,100	614,200
Property, plant and equipment, at cost less accumulated depreciation and amortization of $974.2 in 2018 and $874.7 in 2017	1,748,200	1,679,500
Other assets	42,500	37,300
Total assets	2,360,800	2,331,000	2,088,700
Current liabilities
Current maturities of long-term debt	21,200	19,900
Trade accounts payable and accrued liabilities	456,900	513,400
Total current liabilities	478,100	533,300
Long-term debt, including capitalized lease obligations	842,100	860,900
Deferred income taxes	192,200	154,200
Asset retirement obligations	30,700	28,200
Deferred credits and other liabilities	10,400	16,000
Total liabilities	1,553,500	1,592,600
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 and 46,767,164 shares issued at December 2018 and 2017, respectively)	500	500
Treasury stock (14,505,681 and 12,675,630 shares held at December 31, 2018 and 2017, respectively)	(940,300)	(806,500)
Additional paid in capital (APIC)	539,000	549,900
Retained earnings	1,208,100	994,500
Total stockholders' equity	807,300	738,400	$ 697,000	$ 792,200
Total liabilities and stockholders' equity	$ 2,360,800	$ 2,331,000

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Accounts receivable - trade, allowance for doubtful accounts	$ 1.1	$ 1.1
Accumulated depreciation and amortization	$ 974.2	$ 874.7
Preferred stock par value (in dollars per share)	$ 0.01	$ 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)	14,505,681	12,675,630

Consolidated Income Statements

Consolidated Income Statements - USD ($) shares in Thousands, $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Revenues
Operating revenues		$ 3,501.7	$ 3,788	$ 3,829	$ 3,244.2	$ 3,379.5	$ 3,236.3	$ 3,211.2	$ 2,999.6	$ 14,362.9	$ 12,826.6	$ 11,594.6
Operating Expenses
Station and other operating expenses										541.3	514.9	493.3
Depreciation and amortization										134	116.9	98.6
Selling, general and administrative										136.2	141.2	122.7
Accretion of asset retirement obligations										2	1.8	1.6
Total operating expenses										14,087.1	12,539.4	11,294.7
Net settlement proceeds										50.4	0	0
Gain (loss) on sale of assets										(1.1)	(3.9)	88.2
Income from operations										325.1	283.3	388.1
Other income (expense)
Interest income										1.5	1.3	0.6
Interest expense										(52.9)	(46.7)	(39.7)
Other nonoperating income (expense)										0.2	2.2	3.1
Total other income (expense)										(51.2)	(43.2)	(36)
Income before income taxes		100.5	57	69.1	47.3	51.2	108.8	89.9	(9.8)	273.9	240.1	352.1
Income tax expense (benefit)										60.3	(5.2)	130.6
Net Income		$ 77.5	$ 45	$ 51.8	$ 39.3	$ 124.9	$ 67.9	$ 55.5	$ (3)	$ 213.6	$ 245.3	$ 221.5
Basic and Diluted Earnings Per Common Share
Basic (in dollars per share)		$ 2.40	$ 1.40	$ 1.59	$ 1.17	$ 3.62	$ 1.92	$ 1.52	$ (0.08)	$ 6.54	$ 6.85	$ 5.64
Diluted (in dollars per share)		$ 2.38	$ 1.38	$ 1.58	$ 1.16	$ 3.58	$ 1.90	$ 1.51	$ (0.08)	$ 6.48	$ 6.78	$ 5.59
Weighted-average shares outstanding (in thousands):
Basic (in shares)										32,674	35,816	39,269
Diluted (in shares)										32,983	36,156	39,646
Supplemental information:
Excise taxes										$ 1,838.9	$ 1,973.1	$ 1,961.5
Petroleum product sales
Operating Revenues
Operating revenues										11,858.4	10,287.9	9,070.6
Operating Expenses
Operating expenses	[1]									11,251.1	9,773.2	8,604
Merchandise
Operating Revenues
Operating revenues										2,423	2,372.7	2,338.6
Operating Expenses
Operating expenses										2,022.5	1,991.4	1,974.5
Other operating revenues
Operating Revenues
Operating revenues										$ 81.5	$ 166	$ 185.4
[1]	Years Ended December 31,(Millions of dollars except per share amounts)2018 2017 2016 Supplemental information: (a) Includes excise taxes of:$1,838.9 $1,973.1 $1,961.5

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Activities
Net income	$ 213,600	$ 245,300	$ 221,500
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	134,000	116,900	98,600
Deferred and noncurrent income tax charges (benefits)	37,900	(50,400)	40,400
Accretion of asset retirement obligations	2,000	1,800	1,600
Pretax (gains) losses from sale of assets	1,100	3,900	(88,200)
Net decrease (increase) in noncash operating working capital	2,300	(36,900)	53,700
Other operating activities - net	7,800	3,000	9,800
Net cash provided by operating activities	398,700	283,600	337,400
Investing Activities
Property additions	(204,300)	(258,300)	(262,100)
Proceeds from sale of assets	1,200	900	85,300
Changes in restricted cash	0	0	68,600
Other investing activities - net	(6,000)	(4,700)	(29,000)
Other	0	0	2,400
Net cash required by investing activities	(209,100)	(262,100)	(134,800)
Financing Activities
Purchase of treasury stock	(144,400)	(206,000)	(323,300)
Repayments of long-term debt	(21,300)	(131,400)	(20,400)
Additions to long-term debt	0	338,800	200,000
Debt issuance costs	0	(1,100)	(3,200)
Amounts related to share-based compensation	(9,400)	(5,600)	(4,200)
Net cash required by financing activities	(175,100)	(5,300)	(151,100)
Net change in cash and cash equivalents	14,500	16,200	51,500
Cash, cash equivalents, and restricted cash at January 1	170,000	153,800	102,300
Cash, cash equivalents, and restricted cash at December 31	184,500	170,000	153,800
Reconciliation of Cash, Cash Equivalents and Restricted Cash
Cash, cash equivalents, and restricted cash	$ 170,000	$ 153,800	$ 102,300

Consolidated Statements of Chan

Consolidated Statements of Changes in Equity - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock	APIC	Retained Earnings
Balance at Dec. 31, 2015	$ 792,200	$ 500	$ (294,100)	$ 558,100	$ 527,700
Balance (in shares) at Dec. 31, 2015		46,767,164
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	221,500				221,500
Purchase of treasury stock	(323,300)		(323,300)
Issuance of common stock	0	$ 0
Issuance of treasury stock	0		9,400	(9,400)
Amounts related to share-based compensation	(2,700)			(2,700)
Share-based compensation expense	9,300			9,300
Balance at Dec. 31, 2016	697,000	$ 500	(608,000)	555,300	749,200
Balance (in shares) at Dec. 31, 2016		46,767,164
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	245,300				245,300
Purchase of treasury stock	(206,000)		(206,000)
Issuance of common stock	0	$ 0
Issuance of treasury stock	100		7,500	(7,400)
Amounts related to share-based compensation	(5,600)			(5,600)
Share-based compensation expense	7,600			7,600
Balance at Dec. 31, 2017	$ 738,400	$ 500	(806,500)	549,900	994,500
Balance (in shares) at Dec. 31, 2017	46,767,164	46,767,164
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 213,600				213,600
Purchase of treasury stock	(144,400)		(144,400)
Issuance of common stock	0	$ 0
Issuance of treasury stock	0		10,600	(10,600)
Amounts related to share-based compensation	(9,400)			(9,400)
Share-based compensation expense	9,100			9,100
Balance at Dec. 31, 2018	$ 807,300	$ 500	$ (940,300)	$ 539,000	$ 1,208,100
Balance (in shares) at Dec. 31, 2018	46,767,164	46,767,164

Description of Business and Bas

Description of Business and Basis of Presentation	12 Months Ended
	Dec. 31, 2018
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. Murphy USA markets refined products through a network of retail gasoline stores and unbranded wholesale customers. Murphy USA’s owned retail stores are almost all located in close proximity to Walmart stores in 26 states and use the brand name Murphy USA®. Murphy USA also markets gasoline and other products at standalone stores under the Murphy Express brand. At December 31, 2018 , Murphy USA had a total of 1,472 Company stores. The Company also has certain product supply and wholesale assets, including product distribution terminals and pipeline positions.

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
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 2018 , $2.0 billion in 2017 , and $2.0 billion in 2016 . CASH EQUIVALENTS – Short-term investments, which include government securities, money market funds and other instruments with government securities as collateral, that have an original 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 in 2018 was $2.2 million and $3.8 million in 2017. 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, 2018 and December 31, 2017 , 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’s results of operations were included in the consolidated federal income tax return of Murphy Oil prior to the separation, while in most cases, these results have been included in the various state tax returns of Murphy USA historically. 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. See Note 12 and Note 15 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 for 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 estimates. On an ongoing basis, we review our estimates based on currently available information. Changes in facts and circumstances may result in revised estimates.

Revenues

Revenues	12 Months Ended
	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Revenues	Revenues Adoption of ASC Topic 606, "Revenue from Contracts with Customers" On January 1, 2018, we adopted Topic 606 using the modified retrospective method applied to those contracts which were not completed as of January 1, 2018. Results for reporting periods beginning after January 1, 2018 are presented under Topic 606, while prior period amounts are not adjusted and continue to be reported in accordance with our historical accounting policies under Topic 605. There was no material impact to opening retained earnings as a result of adoption of Topic 606 that resulted in a cumulative effect adjustment. The following tables disaggregates our revenue by major source for the years ended December 31, 2018 and 2017 and 2016. Years Ended December 31, (Millions of dollars) 2018 2017 2016 Marketing Segment Petroleum product sales (at retail) 1 $ 10,459.2 $ 9,041.5 $ 8,087.4 Petroleum product sales (at wholesale) 1 1,399.2 1,246.4 980.5 Other Petroleum product sales — — 2.7 Total petroleum product sales 11,858.4 10,287.9 9,070.6 Merchandise sales 2,423.0 2,372.6 2,338.6 Other operating revenues: RINs 75.2 160.3 181.2 Other revenues 2 5.7 5.4 3.9 Total marketing segment revenues 14,362.3 12,826.2 $ 11,594.3 Corporate and Other Assets 0.6 0.4 $ 0.3 Total revenues $ 14,362.9 $ 12,826.6 $ 11,594.6 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 The Company adopted ASC Topic 606 as of January 1, 2018 using the modified retrospective method. The impact of the excise and sales taxes collected and remitted to government authorities included in petroleum product sales that would have been recognized under previous revenue recognition guidance would have increased 2018 petroleum product sales (at retail) by $25.4 million and petroleum product sales (at wholesale) by $171.2 million for a total increase in petroleum product sales of $196.5 million . 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 to seven days, depending on the terms with the particular credit/debit card providers. Payment fees retained by the credit/debit card providers are recorded as station and other operating expenses. 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. 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 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. Due to the limited nature of the pilot program and the short amount of time the program has been in effect, the deferred revenues recorded in the year 2018 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 Trade accounts receivable on the balance sheet represents both receivables related to contracts with customers and other trade receivables. At December 31, 2018 and December 31, 2017, we had $79.4 million and $145.6 million of receivables, respectively, related to contracts with customers recorded. All of the trade accounts receivable related to contracts with customers outstanding at December 31, 2018 and December 31, 2017 were considered to be short term. These receivables were generally related to credit and debit card transactions along with short term bulk and wholesale sales from our customers, which have a very short settlement window.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2018
Inventory Disclosure [Abstract]
Inventories	Inventories Inventories consisted of the following: December 31, (Millions of dollars) 2018 2017 Finished products - FIFO basis $ 219.4 $ 231.9 Less LIFO reserve - finished products (115.5 ) (167.2 ) Finished products - LIFO basis 103.9 64.7 Store merchandise for resale 107.2 104.8 Materials and supplies 10.4 13.0 Total inventories $ 221.5 $ 182.5 At December 31, 2018 and 2017 , the replacement cost (market value) of last-in, first-out (LIFO) inventories exceeded the LIFO carrying value by $115.5 million and $167.2 million , respectively.

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Property, Plant and Equipment December 31, 2018 December 31, 2017 (Millions of dollars) Estimated Useful Life Cost Net Cost Net Land $ 591.9 $ 591.9 $ 586.5 $ 586.5 Pipeline and terminal facilities 16 to 25 years 73.1 41.6 72.0 43.0 Retail gasoline stations 3 to 50 years 1,890.6 1,018.5 1,752.6 968.9 Buildings 20 to 45 years 55.0 41.8 54.6 42.9 Other 3 to 20 years 111.8 54.4 88.5 38.2 $ 2,722.4 $ 1,748.2 $ 2,554.2 $ 1,679.5 Depreciation expense of $133 million , $115 million and $97 million was recorded for the years ended December 31, 2018 , 2017 and 2016 , respectively.

Accounts Payable and Accrued Li

Accounts Payable and Accrued Liabilities	12 Months Ended
	Dec. 31, 2018
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) 2018 2017 Trade accounts payable $ 274.9 $ 339.6 Excise taxes/withholdings payable 89.7 89.4 Accrued insurance obligations 21.8 21.4 Accrued taxes other than income 26.6 25.3 Other 43.9 37.7 Accounts payable and accrued liabilities $ 456.9 $ 513.4

Long-Term Debt

Long-Term Debt	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt Long-term debt consisted of the following: December 31, (Millions of dollars) 2018 2017 6.00% senior notes due 2023 (net of unamortized discount of $4.1 at 2018 and $5.0 at 2017) $ 495.9 $ 495.0 5.625% senior notes due 2027 (net of unamortized discount of $3.1 at 2018 and $3.5 at 2017) 296.9 296.5 Term loan due 2020 (effective rate of 5.0% at 2018 and 4.15% at 2017 ) 72.0 92.0 Capitalized lease obligations, vehicles, due through 2022 2.3 2.4 Unamortized debt issuance costs (3.8 ) (5.1 ) Total long-term debt 863.3 880.8 Less current maturities 21.2 19.9 Total long-term debt, net of current $ 842.1 $ 860.9 Senior Notes On August 14, 2013, Murphy Oil USA, Inc., our primary operating subsidiary, issued 6.00% Senior Notes due 2023 (the “2023 Senior Notes”) in an aggregate principal amount of $500 million . The 2023 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 2023 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 April 25, 2017, Murphy Oil USA, Inc., 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 are essentially identical to the covenants for the 2023 Senior Notes. The 2023 and 2027 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 2023 and 2027 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. Credit Facilities and Term Loan On August 30, 2013, we entered into a credit agreement, which provides for a committed $450 million asset-based loan (ABL) facility (with availability subject to the borrowing base described below) and a $150 million term facility. It also provided for a $200 million uncommitted incremental facility. On September 2, 2014, we amended the credit agreement to extend the maturity date to September 2, 2019 and amend the terms of the various covenants. On March 10, 2016, we amended the agreement to extend the effective date of the ABL to March 10, 2021 , added a $200 million term loan facility that was immediately drawn down and is due on March 10, 2020 and requires quarterly principal payments of $10 million that began July 1, 2016 (now $5 million per quarter), and reduced the uncommitted incremental facility to $150 million . 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 $200 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 consecutive business days is less than the greater of (a) 17.5% of the lesser of the aggregate ABL facility commitments and the borrowing base and (b) $70,000,000 (including as of the most recent fiscal quarter end on the first date when availability is less than such amount) as well as a maximum secured debt to EBITDA ratio of 4.5 to 1.0 at any time when term facility commitments or term loans thereunder are outstanding. As of December 31, 2018 , our fixed charge coverage ratio was 1.10 . Our secured debt to EBITDA ratio as of December 31, 2018 was 0.16 to 1.0. 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, 2018 , our ability to make restricted payments was not limited as our fixed charge coverage ratio was greater than 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.

Asset Retirement Obligations (A

Asset Retirement Obligations (ARO)	12 Months Ended
	Dec. 31, 2018
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, 2018 and 2017 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) 2018 2017 Balance at beginning of period $ 28.2 $ 26.2 Accretion expense 2.0 1.8 Settlements of liabilities (0.3 ) (0.3 ) Liabilities incurred 0.8 0.5 Balance at end of period $ 30.7 $ 28.2 The estimation of future ARO is based on a number of assumptions requiring professional judgment. The Company cannot predict the type of revisions to these assumptions that may be required in future periods due to the lack of availability of additional information.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The components of income from continuing operations before income taxes for each of the three years ended December 31, 2018 and income tax expense (benefit) attributable thereto were as follows: Years Ended December 31, (Millions of dollars) 2018 2017 2016 Income (loss) from continuing operations before income taxes $ 273.9 $ 240.1 $ 352.1 Income tax expense (benefit) Federal - Current $ 18.4 39.2 74.9 Federal - Deferred 31.0 (50.7 ) 38.8 State - Current and deferred 10.9 6.3 16.9 Total $ 60.3 $ (5.2 ) $ 130.6 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) 2018 2017 2016 Income tax expense based on the U.S. statutory tax rate $ 57.5 $ 84.0 $ 123.2 State income taxes, net of federal benefit 8.3 3.0 11.5 Effect of U.S. tax law change — (88.9 ) — Other, net (5.5 ) (3.3 ) (4.1 ) Total $ 60.3 $ (5.2 ) $ 130.6 An analysis of the Company’s deferred tax assets and deferred tax liabilities at December 31, 2018 and 2017 showing the tax effects of significant temporary differences is as follows: December 31, (Millions of dollars) 2018 2017 Deferred tax assets Property costs and asset retirement obligations $ 3.3 $ 2.8 Employee benefits 6.3 4.4 Other deferred tax assets 2.6 3.5 Total gross deferred tax assets 12.2 10.7 Deferred tax liabilities Accumulated depreciation and amortization (171.6 ) (142.1 ) State deferred taxes (25.9 ) (18.9 ) Other deferred tax liabilities (6.9 ) (3.9 ) Total gross deferred tax liabilities (204.4 ) (164.9 ) Net deferred tax liabilities $ (192.2 ) $ (154.2 ) 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. In December 2017, the Tax Cuts and Jobs Act ("the Act") was enacted, which made major changes to the Federal income tax system for corporations and individuals. Two key corporate provisions of the Act that impacted the Company in 2017 were the reduction of the Federal corporate income tax rate from 35% to 21% and the increase of Federal bonus depreciation from 50% to 100% on certain qualifying assets retroactive to September 27, 2017. As a result, the Company calculated the impact of the Act in its year-end income tax provision in accordance with its understanding of the Act and guidance available as of the date of the filing and as a result recorded $88.9 million as a tax benefit in the fourth quarter of 2017, the period in which the legislation was enacted. The provisional amount related primarily to the remeasurement of certain deferred tax assets and liabilities based on the rates of which they are expected to reverse in the future. In conjunction with the effectiveness of the Act, the SEC issued Staff Accounting Bulletin No. 118 ("SAB 118") to address the implications of U.S. GAAP in situations where the registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the Act. In accordance with SAB 118, the Company made its best estimate and recorded provisional amounts related to certain equity and fixed asset temporary differences based on available information as of December 31, 2017. These amounts were finalized in the fourth quarter of 2018 and with immaterial adjustments being recorded as a component of tax expense. The Company was included in Murphy Oil’s tax returns for the periods prior to separation and include state jurisdictions that are subject to audit by taxing authorities. These audits often take years to complete and settle. As of December 31, 2018 , the earliest year remaining open for Federal audit and/or settlement is 2015 and for the states it ranges from 2013 - 2017 . 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, 2018 and 2017 is shown in the following table. Year Ended December 31, (Millions of dollars) 2018 2017 Balance at January 1 $ 4.4 $ 7.9 Additions for tax positions related to prior years — 4.4 Additions for tax positions related to current year 0.2 — Settlements with taxing authorities (3.9 ) (5.5 ) Expiration of statutes of limitation — (2.4 ) Balance at December 31 $ 0.7 $ 4.4 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, 2018 , 2017 and 2016 included interest and penalties of $(1.6) million , $0.4 million , and $1.5 million , respectively, associated with uncertain tax positions. During the next twelve months, the Company currently expects to add immaterial amounts to the liability for uncertain taxes for 2019 events. 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 2019 . We adopted ASU 2016-09 on January 1, 2017, which requires the excess tax benefits or deficiencies to be reflected in the Consolidated Statements of Income as a component of the provision for income taxes whereas they previously were recognized in paid-in-capital. Total excess tax benefits recognized in the twelve months ended December 31, 2018 and 2017 was $2.5 million and $2.2 million , respectively.

Incentive Plans

Incentive Plans	12 Months Ended
	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Incentive Plans	Incentive Plans Prior to the separation, our employees participated in the Murphy Oil 2007 Long-Term Incentive Plan (the “2007 Plan”) and the Murphy Oil 2012 Long-Term Incentive Plan (the “2012 Plan”) and received Murphy Oil restricted stock awards and options to purchase shares of Murphy Oil common stock. While participating in these two plans, costs resulting from share-based payment transactions were allocated and recognized as an expense in the financial statements using a fair value-based measurement method over the periods that the awards vested. 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 12, 2014 (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), cash awards, and performance awards to our employees. Prior to the amendment and restatement of the MUSA 2013 Plan on February 12, 2014, 10 million shares of MUSA common stock were authorized to be delivered under the MUSA 2013 Plan over the life of the plan. Pursuant to the amendment and restatement of the plan effective as of February 12, 2014, this was reduced to 5.5 million shares of common stock. 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 million . In connection with the separation, stock compensation awards granted under the 2007 Plan and the 2012 Plan by Murphy Oil (pre-separation awards) were adjusted or substituted as follows: • Vested stock options were equitably adjusted so that the grantee holds more options to purchase Murphy Oil common stock at a lower strike price. • Unvested stock options and stock appreciation rights held by MUSA employees were replaced with substitute awards of options to purchase shares of MUSA common stock. • Unvested restricted stock units will be replaced with adjusted, substitute awards for restricted stock units of MUSA common stock. The new awards of restricted stock are intended to generally preserve the intrinsic value of the original award determined as of the separation and distribution date. • Vesting periods of awards were unaffected by the adjustment and substitution, except that for vested Murphy Oil stock options the MUSA employees have until the earlier of two years from the date of the separation or the stated expiration date of the option to exercise the award. Awards granted in connection with the adjustment and substitution of awards originally issued under the 2007 Plan and the 2012 Plan are a part of the MUSA 2013 Plan and reduce the maximum number of shares of common stock available for delivery under the MUSA 2013 Plan. During the period from August 30, 2013 to December 31, 2018 , the Company granted a total of 2,053,499 awards from the MUSA 2013 Plan which leaves 3,446,501 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, 110,543 time-based restricted stock units have been granted under the terms of the Directors Plan which leaves 389,457 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. All expense prior to August 30, 2013 was incurred under the 2007 Plan and the 2012 Plan while all amounts after August 30, 2013 were incurred in the MUSA 2013 Plan and the Directors Plan. December 31, (Millions of dollars) 2018 2017 2016 Compensation charged against income before income tax benefit $ 9.2 $ 7.5 $ 9.3 Related income tax benefit recognized in income $ 1.9 $ 2.6 $ 3.3 As of December 31, 2018 , there was $12.2 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 $2.1 million , $0.6 million , and $1.6 million for the years ended December 31, 2018 , 2017 , and 2016 , respectively. 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. Each option granted through December 31, 2013 under the MUSA 2013 Plan was nonqualified and was issued to replace awards of Murphy Oil that were previously granted to employees of the Company prior to the separation from Murphy Oil. The remaining term of each option granted mirrored the remaining term of the original award that it replaced and the exercise price was adjusted based on the terms of the Employee Matters Agreement entered into between the Company and Murphy Oil in connection with the separation. Post separation in 2013, the only awards issued were to replace the unvested awards of Murphy Oil that were forfeited in conjunction with the separation. Therefore, the accounting for those awards was a continuation of the Murphy Oil fair value that was previously calculated using the Black-Scholes pricing model and used the following original assumptions to calculate the fair value used for expense purposes. Following are the assumptions used originally by Murphy Oil to value the original awards. Years Ended December 31, 2012 and 2011 Fair value per option grant 12.37 - 20.34 Assumptions Dividend yield 1.80% - 2.27% Expected volatility 37.00% - 39.62% Risk-free interest rate 0.55% - 2.10% Expected life 4.00 yrs. - 5.20 yrs. As a result of the separation from Murphy Oil, the unvested Murphy Oil options were replaced with an appropriate number of Company options bearing an exercise price that was adjusted to preserve the intrinsic value near the date of the separation in connection with the terms of the Employee Matters Agreement. The grant date fair values of the options replaced with MUSA 2013 Plan awards ranged from $32.53 to $40.25 . Because of these adjustments, no further Black-Scholes fair values were required to be calculated for the post separation period. The adjustment and substitution of the stock compensation awards occurred in conjunction with the distribution of MUSA common stock to Murphy Oil stockholders. As a result, no grant, exercise, or cancellation activity occurred on MUSA stock compensation awards during the year ended December 31, 2013. In February 2018 , 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: Year Ended December 31, 2018 2017 2016 Fair value per option grant $ 17.32 $ 15.45 $ 16.08 Assumptions Dividend yield — — — Expected volatility 27.0 % 26.0 % 26.1 % Risk-free interest rate 2.43 % 1.65 % 1.26 % Expected life 3.9 years 4.2 years 5.7 years Changes in options outstanding for Company employees during the period from December 31, 2015 to December 31, 2018 are presented in the following table: Number of Shares Average Exercise Price Outstanding at December 31, 2015 465,756 $ 42.22 Granted at FMV 96,500 59.11 Vested and issued (126,969 ) 34.48 Forfeited (14,350 ) 58.28 Outstanding at December 31, 2016 420,937 47.88 Granted at FMV 114,800 65.75 Exercised (43,887 ) 37.41 Forfeited (25,950 ) 63.63 Outstanding at December 31, 2017 465,900 52.39 Granted at FMV 97,600 71.07 Exercised (220,938 ) 39.48 Forfeited (32,200 ) 69.21 Outstanding at December 31, 2018 310,362 $ 65.71 Exercisable at December 31, 2016 218,937 $ 38.32 Exercisable at December 31, 2017 254,375 $ 42.80 Exercisable at December 31, 2018 100,662 $ 64.17 Additional information about stock options outstanding at December 31, 2018 is shown below: Options Outstanding Options Exercisable Range of Exercise Prices per Option No. of Options Avg. Life Remaining in Years Aggregate Intrinsic Value No. of Options Avg. Life Remaining in Years Aggregate Intrinsic Value $32.53 to $39.99 7,062 3.2 $ 280,472 7,062 3.2 $ 280,472 $40.00 to $59.99 74,800 4.1 1,311,244 35,500 4.1 622,315 $60.00 to $69.99 94,000 5.1 1,023,660 — 0.0 — $70.00 to $79.99 134,500 4.8 776,363 58,100 3.0 352,667 310,362 4.7 $ 3,391,739 100,662 3.4 $ 1,255,454 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. During 2018 , the Committee granted time-based restricted stock units to certain employees and the weighted average grant date fair value was determined to be $71.91 per unit. These awards were granted under the MUSA 2013 Plan and vest over 3 years . Changes in restricted stock units outstanding for Company employees during the period from December 31, 2015 to December 31, 2018 are presented in the following table: (Number of units) Employee RSU's Outstanding at December 31, 2015 356,300 Granted at FMV 74,325 Vested and issued (142,392 ) Forfeited (18,888 ) Outstanding at December 31, 2016 269,345 Granted at FMV 111,471 Vested and issued (60,688 ) Forfeited (61,112 ) Outstanding at December 31, 2017 259,016 Granted FMV 69,179 Vested and issued (96,815 ) Forfeited (37,902 ) Outstanding at December 31, 2018 193,478 PERFORMANCE-BASED RESTRICTED STOCK UNITS (MUSA 2013 Plan) – In February 2018 , the Committee awarded performance-based restricted stock units (performance units) to certain employees. Half of the performance units vest based on a 3 -year return on average capital employed (ROACE) calculation and the other half vest based on a 3 -year total shareholder return (TSR) calculation that compares MUSA to a group of 16 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 $87.60 per unit. For the ROACE portion of the awards, the valuation was based on the grant date fair value of $71.00 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, 2015 to December 31, 2018 are presented in the following table: (Number of units) Employee PSU's Outstanding at December 31, 2015 102,394 Granted 53,300 Vested and issued — Forfeited (7,954 ) Outstanding at December 31, 2016 147,740 Granted 53,800 Vested and issued (60,816 ) Forfeited (16,000 ) Outstanding at December 31, 2017 124,724 Granted 66,284 Vested and issued (51,296 ) Forfeited (15,300 ) Outstanding at December 31, 2018 124,412 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 and the grant fair value was $69.42 per unit. 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, 2015 to December 31, 2018 are presented in the following table: (Number of units) Director RSU's Outstanding at December 31, 2015 63,774 Granted at FMV 19,900 Vested and issued (34,332 ) Forfeited — Outstanding at December 31, 2016 49,342 Granted at FMV 15,948 Vested and issued (19,944 ) Forfeited — Outstanding at December 31, 2017 45,346 Granted at FMV 10,921 Vested and issued (15,250 ) Forfeited — Outstanding at December 31, 2018 41,017

Employee and Retiree Benefit Pl

Employee and Retiree Benefit Plans	12 Months Ended
	Dec. 31, 2018
Retirement Benefits [Abstract]
Employee and Retiree Benefit Plans	Employee and Retiree Benefit Plans THRIFT PLAN – At the time of the spin-off, Murphy USA set up a new qualified defined contribution plan for full-time employees with an asset transfer from the Murphy Oil defined contribution plan. Most full-time employees of the Company may participate in 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 for this plan were $9.7 million in 2018 , $12.1 million in 2017 and $10.5 million in 2016 . 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 $(0.8) million in 2018 , $2.2 million in 2017 and $1.8 million in 2016 .

Financial Instruments and Risk

Financial Instruments and Risk Management	12 Months Ended
	Dec. 31, 2018
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. 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”). As of December 31, 2018 , all current derivative activity is immaterial. At December 31, 2018 and 2017 cash deposits of $1.0 million and $2.7 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, 2018 and 2017 .

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2018
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 August 30, 2013, 46,743,316 shares of our common stock were distributed to the shareholders of Murphy Oil in connection with the separation. For comparative purposes, we have assumed this amount to be outstanding as of the beginning of each prior period prior to the separation presented in the calculation of weighted average shares outstanding. During May 2014, the Company authorized a share repurchase program that was approved by the Board of Directors for approximately $50 million worth of common stock of the Company. At the completion of this program, the Company had acquired 1,040,636 shares of common stock for an average price of $48.07 per share including brokerage fees. In October 2014, the Company announced a $250 million share repurchase program that was completed prior to the end of 2015. In this repurchase, 4,196,349 shares were repurchased for an average price of $59.58 per share. On January 25, 2016, the Company announced that it would proceed with an independent growth plan in which we will concentrate on acquiring land from third parties rather than acquiring land directly from Walmart. In conjunction with this announcement, the Board of Directors approved a strategic allocation of capital for the Company to pursue new additional growth opportunities and to undertake a share repurchase program of the Company's common stock. The Board authorized up to $500 million in total for the two capital programs through December 31, 2017. For the year ended December 31, 2017, the Company acquired 2,586,190 shares of common stock for an average price of $68.34 per share including brokerage fees which included completion of the $500 million repurchase program. Based on market conditions and other factors, the Company repurchased an additional 379,054 common shares for $29 million , with an average price of $77.20 , during the fourth quarter of 2017. Upon completion of the most recent repurchase plan authorized by the Murphy USA Inc. Board of Directors in December 2017, the Company remains committed to share repurchases under quarterly allocations in line with its past practice, subject to market conditions and cash availability. During 2018 the Company acquired 1,994,632 common shares for $144.4 million , with an average price of $72.39 per share including brokerage fees. The following table provides a reconciliation of basic and diluted earnings per share computations for the years ended December 31, 2018 , 2017 and 2016 (in millions, except per share amounts): Years ended December 31, (Millions of dollars except per share amounts) 2018 2017 2016 Earnings per common share: Net income per share - basic Net income attributable to common stockholders $ 213.6 $ 245.3 $ 221.5 Weighted average common shares outstanding (in thousands) 32,674 35,816 39,269 Earnings per common share $ 6.54 $ 6.85 $ 5.64 Earnings per common share - assuming dilution: Net income per share - diluted Net income attributable to common stockholders $ 213.6 $ 245.3 $ 221.5 Weighted average common shares outstanding (in thousands) 32,674 35,816 39,269 Common equivalent shares: Share-based awards 309 340 377 Weighted average common shares outstanding - assuming dilution (in thousands) 32,983 36,156 39,646 Earnings per common share assuming dilution $ 6.48 $ 6.78 $ 5.59 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. For the reported periods, the number of time-based restrictive stock units, performance based units and non-qualified stock options that are excluded due to their anti-dilutive nature is immaterial.

Other Financial Information

Other Financial Information	12 Months Ended
	Dec. 31, 2018
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 $17.4 million , $51.7 million and $70.8 million for the three years ended December 31, 2018 , 2017 and 2016 , respectively. Interest paid, net of amounts capitalized, was $50.4 million , $41.5 million and $37.1 million for the years ended December 31, 2018 , 2017 and 2016 , respectively. CHANGES IN WORKING CAPITAL - (Millions of dollars) 2018 2017 2016 Accounts receivable $ 86.6 $ (41.7 ) $ (47.2 ) Inventories (39.0 ) (16.3 ) 2.1 Prepaid expenses and other current assets 11.4 (5.2 ) 13.7 Accounts payable and accrued liabilities (56.7 ) 26.9 83.4 Income taxes payable — (0.6 ) 1.7 Net decrease (increase) in noncash operating working capital $ 2.3 $ (36.9 ) $ 53.7

Assets and Liabilities Measure

Assets and Liabilities Measure at Fair Value	12 Months Ended
	Dec. 31, 2018
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 derivatives contracts was determined using NYMEX quoted values but were immaterial. The carrying value of the Company’s Cash and cash equivalents, Accounts receivable-trade, and Trade accounts payable and accrued liabilities approximates fair value. The following table presents the carrying amounts and estimated fair values of financial instruments held by the Company at December 31, 2018 and 2017 . 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, 2018 December 31, 2017 Carrying Carrying (Millions of dollars) Amount Fair Value Amount Fair Value Financial liabilities Current and long-term debt $ (863.3 ) $ (866.7 ) $ (880.8 ) $ (904.9 )

Commitments

Commitments	12 Months Ended
	Dec. 31, 2018
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 $13.7 million in 2019 , $13.3 million in 2020 , $12.5 million in 2021 , $11.7 million in 2022 , and $11.1 million in 2023 . Rental expense for noncancelable operating leases, including contingent payments when applicable, was $15.2 million in 2018 , $14.0 million in 2017 and $23.2 million in 2016 . Commitments for capital expenditures were approximately $240.5 million at December 31, 2018 , including $219.5 million approved for potential construction of future Murphy USA and Murphy Express gasoline stations (including land) at year-end, along with $15.4 million for improvements of existing stations, to be financed with our operating cash flow and/or incurrence of indebtedness. The Company has certain take-or-pay contracts primarily to supply our terminals with a noncancelable remaining term of 2.7 years . At December 31, 2018 , our minimum annual payments under our take-or-pay contracts are estimated to be $7.9 million in 2019 , $7.9 million in 2020 and $4.9 million in 2021 .

Contingencies

Contingencies	12 Months Ended
	Dec. 31, 2018
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, 2018 , 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, 2018 . 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. The Company was contacted by the State of Mississippi to settle alleged violations of the state's Petroleum Underground Storage Tank system requirements at several of the Company's facilities. We have settled this matter with the state's Department of Environmental Quality and paid a civil penalty in June 2018 of $0.1 million . The resolution of this matter did not have a material impact on our results of operations or financial condition. 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, 2018 , 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 $19.8 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, 2018 , the Company had contingent liabilities of $16.1 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.

Recent Accounting and Reporting

Recent Accounting and Reporting Rules	12 Months Ended
	Dec. 31, 2018
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Recent Accounting and Reporting Rules	Recent Accounting and Reporting Rules In February 2016, the FASB issued ASU No. 2016-02, "Leases (Topic 842)" (“ASU 2016-02”). ASU 2016-02 amends the existing accounting standards for lease accounting by recognizing lease assets and lease liabilities on the balance sheet for those leases classified as operating leases under current GAAP. ASU 2016-02 requires that a lessee should recognize a liability to make lease payments (the lease liability) and a right-of-use asset representing its right to use the underlying asset for the lease term on the balance sheet. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018 (including interim periods within those periods) using a modified retrospective approach and early adoption is permitted. The Company will adopt ASU 2016-02 January 1, 2019 using the modified retrospective transition approach, including certain practical expedients, and is in the process of implementing changes to its systems and processes in conjunction with its review of lease agreements. We have implemented a third-party software solution to assist with the accounting under the new standard and are nearing completion of our testing and optimization of the system. The Company is also finalizing procedures to validate the completeness of its inventory of arrangements that meet the new definition of an operating lease, in parallel to documenting internal policy decisions and permitted elections. The most significant change at the date of adoption will be the recognition of both right-of-use assets and deferred lease liabilities of between $100 - $115 million on its balance sheet primarily for existing real estate operating leases as well as additional required disclosures.

Business Segments

Business Segments	12 Months Ended
	Dec. 31, 2018
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 (Millions of dollars) Marketing Other Assets 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 Year ended December 31, 2017 Segment income (loss) $ 295.3 (50.0 ) $ 245.3 Revenues from external customers 12,826.2 0.4 12,826.6 Interest income — 1.3 1.3 Interest expense (0.1 ) (46.6 ) (46.7 ) Income tax expense (benefit) (2.9 ) (2.3 ) (5.2 ) Significant noncash charges (credits) Depreciation and amortization 110.5 6.4 116.9 Accretion of asset retirement obligations 1.8 — 1.8 Deferred and noncurrent income taxes (benefits) (61.3 ) 10.9 (50.4 ) Additions to property, plant and equipment 234.0 39.7 273.7 Total assets at year-end $ 2,023.4 307.6 $ 2,331.0 Year ended December 31, 2016 Segment income (loss) $ 249.8 (28.3 ) $ 221.5 Revenues from external customers 11,594.3 0.3 11,594.6 Interest income — 0.6 0.6 Interest expense (0.1 ) (39.6 ) (39.7 ) Income tax expense (benefit) 147.2 (16.6 ) 130.6 Significant noncash charges (credits) Depreciation and amortization 92.2 6.4 98.6 Accretion of asset retirement obligations 1.6 — 1.6 Deferred and noncurrent income taxes (benefits) 51.3 (10.9 ) 40.4 Additions to property, plant and equipment 239.1 24.8 263.9 Total assets at year-end $ 1,858.0 230.7 $ 2,088.7

Guarantor Subsidiaries

Guarantor Subsidiaries	12 Months Ended
	Dec. 31, 2018
Guarantor Subsidiaries [Abstract]
Guarantor Subsidiaries	Guarantor Subsidiaries Certain of the Company’s 100% owned, domestic subsidiaries (the “Guarantor Subsidiaries”) fully and unconditionally guarantee, on a joint and several basis, certain of the outstanding indebtedness of the Company, including the 6.00% senior notes due 2023 and the 5.625% senior notes due 2027. The following consolidating schedules present financial information on a consolidated basis in conformity with the SEC’s Regulation S-X Rule 3-10(d): CONSOLIDATING BALANCE SHEET (Millions of dollars) December 31, 2018 Assets Parent Company Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Current assets Cash and cash equivalents $ — $ 184.0 $ 0.5 $ — $ — $ 184.5 Accounts receivable—trade, less allowance for doubtful accounts of $1.1 in 2018 — 138.8 — — — 138.8 Inventories, at lower of cost or market — 221.5 — — — 221.5 Prepaid expenses and other current assets — 25.1 0.2 — — 25.3 Total current assets — 569.4 0.7 — — 570.1 Property, plant and equipment, at cost less accumulated depreciation and amortization of $974.2 in 2018 — 1,745.9 2.3 — — 1,748.2 Investments in subsidiaries 2,437.0 144.4 — — (2,581.4 ) — Other assets — 42.5 — — — 42.5 Total assets $ 2,437.0 $ 2,502.2 $ 3.0 $ — $ (2,581.4 ) $ 2,360.8 Liabilities and Stockholders' Equity Current liabilities Current maturities of long-term debt $ — $ 21.2 $ — $ — $ — $ 21.2 Inter-company accounts payable (0.1 ) 203.0 (48.6 ) (154.3 ) — — Trade accounts payable and accrued liabilities — 456.9 — — — 456.9 Total current liabilities (0.1 ) 681.1 (48.6 ) (154.3 ) — 478.1 Long-term debt, including capitalized lease obligations — 842.1 — — — 842.1 Deferred income taxes — 192.2 — — — 192.2 Asset retirement obligations — 30.7 — — — 30.7 Deferred credits and other liabilities — 10.4 — — — 10.4 Total liabilities (0.1 ) 1,756.5 (48.6 ) (154.3 ) — 1,553.5 Stockholders' Equity Preferred Stock, par $0.01 (authorized 20,000,000 shares, none outstanding) — — — — — — Common Stock, par $0.01 (authorized 200,000,000 shares, 46,767,164 shares issued at December 31, 2018) 0.5 — 0.1 — (0.1 ) 0.5 Treasury stock (14,505,681 shares held at December 31, 2018) (940.3 ) — — — — (940.3 ) Additional paid in capital (APIC) 1,195.1 572.8 52.0 87.5 (1,368.4 ) 539.0 Retained earnings 2,181.8 172.9 (0.5 ) 66.8 (1,212.9 ) 1,208.1 Total stockholders' equity 2,437.1 745.7 51.6 154.3 (2,581.4 ) 807.3 Total liabilities and stockholders' equity $ 2,437.0 $ 2,502.2 $ 3.0 $ — $ (2,581.4 ) $ 2,360.8 CONSOLIDATING BALANCE SHEET (Millions of dollars) December 31, 2017 Assets Parent Company Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Current assets Cash and cash equivalents $ — $ 169.9 $ 0.1 $ — $ — $ 170.0 Accounts receivable—trade, less allowance for doubtful accounts of $1.1 in 2017 — 225.2 — — — 225.2 Inventories, at lower of cost or market — 182.5 — — — 182.5 Prepaid expenses and other current assets — 36.5 — — — 36.5 Total current assets — 614.1 0.1 — — 614.2 Property, plant and equipment, at cost less accumulated depreciation and amortization of $874.7 in 2017 — 1,678.3 1.2 — — 1,679.5 Investments in subsidiaries 2,223.4 144.9 — — (2,368.3 ) — Other assets — 37.3 — — — 37.3 Total assets $ 2,223.4 $ 2,474.6 $ 1.3 $ — $ (2,368.3 ) $ 2,331.0 Liabilities and Stockholders' Equity Current liabilities Current maturities of long-term debt $ — $ 19.9 $ — $ — $ — $ 19.9 Inter-company accounts payable 829.2 (624.1 ) (50.8 ) (154.3 ) — — Trade accounts payable and accrued liabilities — 513.4 — — — 513.4 Total current liabilities 829.2 (90.8 ) (50.8 ) (154.3 ) — 533.3 Long-term debt, including capitalized lease obligations — 860.9 — — — 860.9 Deferred income taxes — 154.2 — — — 154.2 Asset retirement obligations — 28.2 — — — 28.2 Deferred credits and other liabilities — 16.0 — — — 16.0 Total liabilities 829.2 968.5 (50.8 ) (154.3 ) — 1,592.6 Stockholders' Equity Preferred Stock, par $0.01 (authorized 20,000,000 shares, none outstanding) — — — — — — Common Stock, par $0.01 (authorized 200,000,000 shares, 46,767,164 shares issued at December 31, 2017) 0.5 — 0.1 — (0.1 ) 0.5 Treasury stock (12,675,630 shares held at December 31, 2017) (806.5 ) — — — — (806.5 ) Additional paid in capital (APIC) 1,205.7 573.1 52.0 87.5 (1,368.4 ) 549.9 Retained earnings 994.5 933.0 — 66.8 (999.8 ) 994.5 Total stockholders' equity 1,394.2 1,506.1 52.1 154.3 (2,368.3 ) 738.4 Total liabilities and stockholders' equity $ 2,223.4 $ 2,474.6 $ 1.3 $ — $ (2,368.3 ) $ 2,331.0 CONSOLIDATING INCOME STATEMENT (Millions of dollars) Year ended December 31, 2018 Operating Revenues Parent Company Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Petroleum product sales $ — $ 11,858.4 $ — $ — $ — $ 11,858.4 Merchandise sales — 2,423.0 — — — 2,423.0 Other operating revenues — 81.5 — — — 81.5 Total operating revenues — 14,362.9 — — — 14,362.9 Operating expenses Petroleum product cost of goods sold — 11,251.1 — — — 11,251.1 Merchandise cost of goods sold — 2,022.5 — — — 2,022.5 Station and other operating expenses — 541.3 — — — 541.3 Depreciation and amortization — 134.0 — — — 134.0 Selling, general and administrative — 136.2 — — — 136.2 Accretion of asset retirement obligations — 2.0 — — — 2.0 Total operating expenses — 14,087.1 — — — 14,087.1 Net settlement proceeds — 50.4 — — — 50.4 Gain (loss) on sale of assets — (1.1 ) — — — (1.1 ) Income from operations — 325.1 — — — 325.1 Other income (expense) Interest income — 1.5 — — — 1.5 Interest expense — (52.9 ) — — — (52.9 ) Other nonoperating income/expense 973.7 (972.9 ) (0.6 ) — — 0.2 Total other income (expense) 973.7 (1,024.3 ) (0.6 ) — — (51.2 ) Income from continuing operations before income taxes 973.7 (699.2 ) (0.6 ) — — 273.9 Income tax expense (benefit) — 60.4 (0.1 ) — — 60.3 Income (loss) 973.7 (759.6 ) (0.5 ) — — 213.6 Equity earnings in affiliates, net of tax 213.6 (0.5 ) — — (213.1 ) — Net Income (Loss) $ 1,187.3 $ (760.1 ) $ (0.5 ) $ — $ (213.1 ) $ 213.6 CONSOLIDATING INCOME STATEMENT (Millions of dollars) Year ended December 31, 2017 Operating Revenues Parent Company Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Petroleum product sales $ — $ 10,287.9 $ — $ — $ — $ 10,287.9 Merchandise sales — 2,372.7 — — — 2,372.7 Ethanol sales and other — 166.0 — — — 166.0 Total operating revenues — 12,826.6 — — — 12,826.6 Operating Expenses Petroleum product cost of goods sold — 9,773.2 — — — 9,773.2 Merchandise cost of goods sold — 1,991.4 — — — 1,991.4 Station and other operating expenses — 514.9 — — — 514.9 Depreciation and amortization — 116.9 — — — 116.9 Selling, general and administrative — 141.2 — — — 141.2 Accretion of asset retirement obligations — 1.8 — — — 1.8 Total operating expenses — 12,539.4 — — — 12,539.4 Gain (loss) on sale of assets — (3.9 ) — — — (3.9 ) Income from operations — 283.3 — — — 283.3 Other income (expense) Interest income — 1.3 — — — 1.3 Interest expense — (46.7 ) — — — (46.7 ) Other nonoperating income — 2.2 — — — 2.2 Total other income (expense) — (43.2 ) — — — (43.2 ) Income from continuing operations before income taxes — 240.1 — — — 240.1 Income tax expense (benefit) — (5.2 ) — — — (5.2 ) Income from continuing operations — 245.3 — — — 245.3 Equity earnings in affiliates, net of tax 245.3 — — — (245.3 ) — Net Income $ 245.3 $ 245.3 $ — $ — $ (245.3 ) $ 245.3 CONSOLIDATING INCOME STATEMENT (Millions of dollars) Year ended December 31, 2016 Operating Revenues Parent Company Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Petroleum product sales $ — $ 9,070.6 $ — $ — $ — $ 9,070.6 Merchandise sales — 2,338.6 — — — 2,338.6 Ethanol sales and other — 185.4 — — — 185.4 Total operating revenues — 11,594.6 — — — 11,594.6 Operating expenses Petroleum product cost of goods sold — 8,604.0 — — — 8,604.0 Merchandise cost of goods sold — 1,974.5 — — — 1,974.5 Station and other operating expenses — 493.3 — — — 493.3 Depreciation and amortization — 98.6 — — — 98.6 Selling, general and administrative — 122.7 — — — 122.7 Accretion of asset retirement obligations — 1.6 — — — 1.6 Total operating expenses — 11,294.7 — — — 11,294.7 Gain (loss) on sale of assets — 88.2 — — — 88.2 Income from operations — 388.1 — — — 388.1 Other income (expense) Interest income — 0.6 — — — 0.6 Interest expense — (39.7 ) — — — (39.7 ) Other nonoperating income — 3.1 — — — 3.1 Total other income (expense) — (36.0 ) — — — (36.0 ) Income from continuing operations before income taxes — 352.1 — — — 352.1 Income tax expense (benefit) — 130.6 — — — 130.6 Income from continuing operations — 221.5 — — — 221.5 Equity earnings in affiliates, net of tax 221.5 — — — (221.5 ) — Net Income $ 221.5 $ 221.5 $ — $ — $ (221.5 ) $ 221.5 CONSOLIDATING STATEMENT OF CASH FLOWS (Millions of dollars) Year ended December 31, 2018 Operating Activities Parent Company Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Net income (loss) $ 1,187.3 $ (760.1 ) $ (0.5 ) $ — $ (213.1 ) $ 213.6 Adjustments to reconcile net income (loss) to net cash provided by operating activities Depreciation and amortization — 134.0 — — — 134.0 Deferred and noncurrent income tax charges (benefits) — 37.9 — — — 37.9 Accretion of asset retirement obligations — 2.0 — — — 2.0 (Gain) loss from sale of assets — 1.1 — — — 1.1 Net decrease (increase) in noncash operating working capital — 2.4 (0.1 ) — — 2.3 Equity in earnings (213.6 ) 0.5 — — 213.1 — Other operating activities - net — 7.8 — — — 7.8 Net cash provided by (required by) operating activities 973.7 (574.4 ) (0.6 ) — — 398.7 Investing Activities Property additions — (203.1 ) (1.2 ) — — (204.3 ) Proceeds from sale of assets — 1.2 — — — 1.2 Other investing activities - net — (6.0 ) — — — (6.0 ) Net cash provided by (required by) investing activities — (207.9 ) (1.2 ) — — (209.1 ) Financing Activities Purchase of treasury stock (144.4 ) — — — — (144.4 ) Repayments of long-term debt — (21.3 ) — — — (21.3 ) Amounts related to share-based compensation — (9.4 ) — — — (9.4 ) Net distributions to parent (829.3 ) 827.1 2.2 — — — Net cash provided by (required by) financing activities (973.7 ) 796.4 2.2 — — (175.1 ) Net change in cash and cash equivalents — 14.1 0.4 — — 14.5 Cash, cash equivalents, and restricted cash at January 1 — 169.9 0.1 — — 170.0 Cash, cash equivalents, and restricted cash at December 31 $ — $ 184.0 $ 0.5 $ — $ — $ 184.5 CONSOLIDATING STATEMENT OF CASH FLOWS (Millions of dollars) Year ended December 31, 2017 Operating Activities Parent Company Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Net income (loss) $ 245.3 $ 245.3 $ — $ — $ (245.3 ) $ 245.3 Adjustments to reconcile net income (loss) to net cash provided by operating activities Depreciation and amortization — 116.9 — — — 116.9 Deferred and noncurrent income tax charges (credits) — (50.4 ) — — — (50.4 ) Accretion of asset retirement obligations — 1.8 — — — 1.8 (Gains) loss from sale of assets — 3.9 — — — 3.9 Net decrease (increase) in noncash operating working capital — (36.9 ) — — — (36.9 ) Equity in earnings (245.3 ) — — — 245.3 — Other operating activities - net — 3.0 — — — 3.0 Net cash provided by (required by) operating activities — 283.6 — — — 283.6 Investing Activities Property additions — (257.1 ) (1.2 ) — — (258.3 ) Proceeds from sale of assets — 0.9 — — — 0.9 Other investing activities - net — (4.7 ) — — — (4.7 ) Net cash provided by (required by) investing activities — (260.9 ) (1.2 ) — — (262.1 ) Financing Activities Purchase of treasury stock (206.0 ) — — — — (206.0 ) Repayments of long-term debt — (131.4 ) — — — (131.4 ) Additions to long-term debt — 338.8 — — — 338.8 Debt issuance costs — (1.1 ) — — — (1.1 ) Amounts related to share-based compensation — (5.6 ) — — — (5.6 ) Net distributions to parent 206.0 (207.3 ) 1.3 — — — Net cash provided by (required by) financing activities — (6.6 ) 1.3 — — (5.3 ) Net change in cash and cash equivalents — 16.1 0.1 — — 16.2 Cash, cash equivalents, and restricted cash at January 1 — 153.8 — — — 153.8 Cash, cash equivalents, and restricted cash at December 31 $ — $ 169.9 $ 0.1 $ — $ — $ 170.0 CONSOLIDATING STATEMENT OF CASH FLOWS (Millions of dollars) Year ended December 31, 2016 Operating Activities Parent Company Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Net income (loss) $ 221.5 $ 221.5 $ — $ — $ (221.5 ) $ 221.5 Adjustments to reconcile net income (loss) to net cash provided by operating activities Depreciation and amortization — 98.6 — — — 98.6 Deferred and noncurrent income tax charges (credits) — 40.4 — — — 40.4 Accretion of asset retirement obligations — 1.6 — — — 1.6 (Gains) loss from sale of assets — (88.2 ) — — — (88.2 ) Net decrease (increase) in noncash operating working capital — 53.7 — — — 53.7 Equity in earnings (221.5 ) — — — 221.5 — Other operating activities - net — 9.8 — — — 9.8 Net cash provided by (required by) operating activities — 337.4 — — — 337.4 Investing Activities Property additions — (262.1 ) — — — (262.1 ) Proceeds from sale of assets — 85.3 — — — 85.3 Changes in restricted cash — 68.6 — — — 68.6 Other investing activities - net — (29.0 ) — — — (29.0 ) Other — 2.4 — — — 2.4 Net cash provided by (required by) investing activities — (134.8 ) — — — (134.8 ) Financing Activities Purchase of treasury stock (323.3 ) — — — — (323.3 ) Repayments of long-term debt — (20.4 ) — — — (20.4 ) Additions to long-term debt — 200.0 — — — 200.0 Debt issuance costs — (3.2 ) — — — (3.2 ) Amounts related to share-based compensation — (4.2 ) — — — (4.2 ) Net distributions to parent 323.3 (323.3 ) — — — — Net cash provided by (required by) financing activities — (151.1 ) — — — (151.1 ) Net change in cash and cash equivalents — 51.5 — — — 51.5 Cash, cash equivalents and restricted cash at January 1 — 102.3 — — — 102.3 Cash, cash equivalents and restricted cash at December 31 $ — $ 153.8 $ — $ — $ — $ 153.8 Reconciliation of Cash, Cash Equivalents and Restricted Cash Cash and cash equivalents at beginning of period $ — $ 33.7 $ — $ — $ — $ 33.7 Restricted cash at beginning of period — 68.6 — — — 68.6 Cash, cash equivalents and restricted cash at beginning of period $ — $ 102.3 $ — $ — $ — $ 102.3 Cash and cash equivalents at end of period $ — $ 153.8 $ — $ — $ — $ 153.8 Restricted cash at end of period — — — — — $ — Cash, cash equivalents and restricted cash at end of period $ — $ 153.8 $ — $ — $ — $ 153.8 CONSOLIDATING STATEMENT OF CHANGES IN EQUITY (Millions of dollars) Year ended December 31, 2018 Statement of Stockholders' Equity Parent Company Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Common Stock Balance as of December 31, 2017 $ 0.5 $ — $ 0.1 $ — $ (0.1 ) $ 0.5 Issuance of common stock — — — — — — Balance as of December 31, 2018 $ 0.5 $ — $ 0.1 $ — $ (0.1 ) $ 0.5 Treasury Stock Balance as of December 31, 2017 $ (806.5 ) $ — $ — $ — $ — $ (806.5 ) Issuance of common stock 10.6 — — — — 10.6 Repurchase of common stock (144.4 ) — — — — (144.4 ) Balance as of December 31, 2018 $ (940.3 ) $ — $ — $ — $ — $ (940.3 ) APIC Balance as of December 31, 2017 $ 1,205.7 $ 573.1 $ 52.0 $ 87.5 $ (1,368.4 ) $ 549.9 Issuance of common stock (10.6 ) — — — — (10.6 ) Amounts related to share-based compensation — (9.4 ) — — — (9.4 ) Share-based compensation expense — 9.1 — — — 9.1 Balance as of December 31, 2018 $ 1,195.1 $ 572.8 $ 52.0 $ 87.5 $ (1,368.4 ) $ 539.0 Retained Earnings Balance as of December 31, 2017 $ 994.5 $ 933.0 $ — $ 66.8 $ (999.8 ) $ 994.5 Net income 1,187.3 (760.1 ) (0.5 ) — (213.1 ) 213.6 Balance as of December 31, 2018 $ 2,181.8 $ 172.9 $ (0.5 ) $ 66.8 $ (1,212.9 ) $ 1,208.1 CONSOLIDATING STATEMENTS OF CHANGES IN EQUITY (Millions of dollars) Year ended December 31, 2017 Statement of Stockholders' Equity Parent Company Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Common Stock Balance as of December 31, 2016 $ 0.5 $ — $ 0.1 $ — $ (0.1 ) $ 0.5 Issuance of common stock — — — — — — Balance as of December 31, 2017 $ 0.5 $ — $ 0.1 $ — $ (0.1 ) $ 0.5 Treasury Stock Balance as of December 31, 2016 $ (608.0 ) $ — $ — $ — $ — $ (608.0 ) Issuance of common stock 7.5 — — — — 7.5 Repurchase of common stock (206.0 ) — — — — (206.0 ) Balance as of December 31, 2017 $ (806.5 ) $ — $ — $ — $ — $ (806.5 ) APIC Balance as of December 31, 2016 $ 1,213.1 $ 571.1 $ 52.0 $ 87.5 $ (1,368.4 ) $ 555.3 Issuance of common stock (7.4 ) — — — — (7.4 ) Amounts related to share-based compensation — (5.6 ) — — — (5.6 ) Reclassification of equity — — — — — — Share-based compensation expense — 7.6 — — — 7.6 Balance as of December 31, 2017 $ 1,205.7 $ 573.1 $ 52.0 $ 87.5 $ (1,368.4 ) $ 549.9 Retained Earnings Balance as of December 31, 2016 $ 749.2 $ 687.7 $ — $ 66.8 $ (754.5 ) $ 749.2 Net income 245.3 245.3 — — (245.3 ) 245.3 Balance as of December 31, 2017 $ 994.5 $ 933.0 $ — $ 66.8 $ (999.8 ) $ 994.5 CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Millions of dollars) Year ended December 31, 2016 Statement of Stockholders' Equity Parent Company Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Common Stock Balance as of December 31, 2015 $ 0.5 $ — $ 0.1 $ — $ (0.1 ) $ 0.5 Issuance of common stock — — — — — — Balance as of December 31, 2016 $ 0.5 $ — $ 0.1 $ — $ (0.1 ) $ 0.5 Treasury Stock Balance as of December 31, 2015 $ (294.1 ) $ — $ — $ — $ — $ (294.1 ) Issuance of common stock 9.4 — — — — 9.4 Repurchase of common stock (323.3 ) — — — — (323.3 ) Balance as of December 31, 2016 $ (608.0 ) $ — $ — $ — $ — $ (608.0 ) APIC Balance as of December 31, 2015 $ 1,222.5 $ 564.5 $ 52.0 $ 87.5 $ (1,368.4 ) $ 558.1 Issuance of common stock (9.4 ) — — — — (9.4 ) Amounts related to share-based compensation — (2.7 ) — — — (2.7 ) Share-based compensation expense — 9.3 — — — 9.3 Balance as of December 31, 2016 $ 1,213.1 $ 571.1 $ 52.0 $ 87.5 $ (1,368.4 ) $ 555.3 Retained Earnings Balance as of December 31, 2015 $ 527.7 $ 466.2 $ — $ 66.8 $ (533.0 ) $ 527.7 Net income 221.5 221.5 — — (221.5 ) 221.5 Balance as of December 31, 2016 $ 749.2 $ 687.7 $ — $ 66.8 $ (754.5 ) $ 749.2

Supplemental Quarterly Informat

Supplemental Quarterly Information (Unaudited)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Supplemental Quarterly Information (Unaudited)	Murphy USA Inc. Supplemental Quarterly Information (Unaudited) First Second Third Fourth (Millions of dollars except per share amounts) Quarter Quarter Quarter Quarter Year Year Ended December 31, 2018 Sales and other operating revenues $ 3,244.2 $ 3,829.0 $ 3,788.0 $ 3,501.7 $ 14,362.9 Income (loss) from continuing operations before income taxes $ 47.3 $ 69.1 $ 57.0 $ 100.5 $ 273.9 Income (loss) from continuing operations $ 39.3 $ 51.8 $ 45.0 $ 77.5 $ 213.6 Net income (loss) $ 39.3 $ 51.8 $ 45.0 $ 77.5 $ 213.6 Income (loss) from continuing operations (per Common share) Basic $ 1.17 $ 1.59 $ 1.40 $ 2.40 $ 6.54 Diluted $ 1.16 $ 1.58 $ 1.38 $ 2.38 $ 6.48 Net income (loss) (per Common share) Basic $ 1.17 $ 1.59 $ 1.40 $ 2.40 $ 6.54 Diluted $ 1.16 $ 1.58 $ 1.38 $ 2.38 $ 6.48 Year Ended December 31, 2017 Sales and other operating revenues $ 2,999.6 $ 3,211.2 $ 3,236.3 $ 3,379.5 $ 12,826.6 Income (loss) from continuing operations before income taxes $ (9.8 ) $ 89.9 $ 108.8 $ 51.2 $ 240.1 Income (loss) from continuing operations $ (3.0 ) $ 55.5 $ 67.9 $ 124.9 $ 245.3 Net income (loss) $ (3.0 ) $ 55.5 $ 67.9 $ 124.9 $ 245.3 Income (loss) from continuing operations (per Common share) Basic $ (0.08 ) $ 1.52 $ 1.92 $ 3.62 $ 6.85 Diluted $ (0.08 ) $ 1.51 $ 1.90 $ 3.58 $ 6.78 Net income (loss) (per Common share) Basic $ (0.08 ) $ 1.52 $ 1.92 $ 3.62 $ 6.85 Diluted $ (0.08 ) $ 1.51 $ 1.90 $ 3.58 $ 6.78

Schedule II - Valuation And Qua

Schedule II - Valuation And Qualifying Accounts	12 Months Ended
	Dec. 31, 2018
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, 2018 Deducted from assets accounts Allowance for doubtful accounts $ 1.1 0.5 (0.5 ) 1.1 2017 Deducted from assets accounts Allowance for doubtful accounts $ 1.9 (0.8 ) — 1.1 2016 Deducted from assets accounts Allowance for doubtful accounts $ 2.0 — (0.1 ) 1.9

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
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	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. 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 to seven days, depending on the terms with the particular credit/debit card providers. Payment fees retained by the credit/debit card providers are recorded as station and other operating expenses. 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. 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 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. Due to the limited nature of the pilot program and the short amount of time the program has been in effect, the deferred revenues recorded in the year 2018 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. On January 1, 2018, we adopted Topic 606 using the modified retrospective method applied to those contracts which were not completed as of January 1, 2018. Results for reporting periods beginning after January 1, 2018 are presented under Topic 606, while prior period amounts are not adjusted and continue to be reported in accordance with our historical accounting policies under Topic 605. There was no material impact to opening retained earnings as a result of adoption of Topic 606 that resulted in a cumulative effect adjustment.
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 an original 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 in 2018 was $2.2 million and $3.8 million in 2017. 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’s results of operations were included in the consolidated federal income tax return of Murphy Oil prior to the separation, while in most cases, these results have been included in the various state tax returns of Murphy USA historically. 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. See Note 12 and Note 15 for further information about the Company’s derivatives.
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 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.
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	In February 2016, the FASB issued ASU No. 2016-02, "Leases (Topic 842)" (“ASU 2016-02”). ASU 2016-02 amends the existing accounting standards for lease accounting by recognizing lease assets and lease liabilities on the balance sheet for those leases classified as operating leases under current GAAP. ASU 2016-02 requires that a lessee should recognize a liability to make lease payments (the lease liability) and a right-of-use asset representing its right to use the underlying asset for the lease term on the balance sheet. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018 (including interim periods within those periods) using a modified retrospective approach and early adoption is permitted. The Company will adopt ASU 2016-02 January 1, 2019 using the modified retrospective transition approach, including certain practical expedients, and is in the process of implementing changes to its systems and processes in conjunction with its review of lease agreements. We have implemented a third-party software solution to assist with the accounting under the new standard and are nearing completion of our testing and optimization of the system. The Company is also finalizing procedures to validate the completeness of its inventory of arrangements that meet the new definition of an operating lease, in parallel to documenting internal policy decisions and permitted elections. The most significant change at the date of adoption will be the recognition of both right-of-use assets and deferred lease liabilities of between $100 - $115 million on its balance sheet primarily for existing real estate operating leases as well as additional required disclosures.

Revenues (Tables)

Revenues (Tables)	12 Months Ended
	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following tables disaggregates our revenue by major source for the years ended December 31, 2018 and 2017 and 2016. Years Ended December 31, (Millions of dollars) 2018 2017 2016 Marketing Segment Petroleum product sales (at retail) 1 $ 10,459.2 $ 9,041.5 $ 8,087.4 Petroleum product sales (at wholesale) 1 1,399.2 1,246.4 980.5 Other Petroleum product sales — — 2.7 Total petroleum product sales 11,858.4 10,287.9 9,070.6 Merchandise sales 2,423.0 2,372.6 2,338.6 Other operating revenues: RINs 75.2 160.3 181.2 Other revenues 2 5.7 5.4 3.9 Total marketing segment revenues 14,362.3 12,826.2 $ 11,594.3 Corporate and Other Assets 0.6 0.4 $ 0.3 Total revenues $ 14,362.9 $ 12,826.6 $ 11,594.6 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
	Dec. 31, 2018
Inventory Disclosure [Abstract]
Summary of Inventory	Inventories consisted of the following: December 31, (Millions of dollars) 2018 2017 Finished products - FIFO basis $ 219.4 $ 231.9 Less LIFO reserve - finished products (115.5 ) (167.2 ) Finished products - LIFO basis 103.9 64.7 Store merchandise for resale 107.2 104.8 Materials and supplies 10.4 13.0 Total inventories $ 221.5 $ 182.5

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Summary of Property, Plant and Equipment	December 31, 2018 December 31, 2017 (Millions of dollars) Estimated Useful Life Cost Net Cost Net Land $ 591.9 $ 591.9 $ 586.5 $ 586.5 Pipeline and terminal facilities 16 to 25 years 73.1 41.6 72.0 43.0 Retail gasoline stations 3 to 50 years 1,890.6 1,018.5 1,752.6 968.9 Buildings 20 to 45 years 55.0 41.8 54.6 42.9 Other 3 to 20 years 111.8 54.4 88.5 38.2 $ 2,722.4 $ 1,748.2 $ 2,554.2 $ 1,679.5

Accounts Payable And Accrued _2

Accounts Payable And Accrued Liabilities (Tables)	12 Months Ended
	Dec. 31, 2018
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) 2018 2017 Trade accounts payable $ 274.9 $ 339.6 Excise taxes/withholdings payable 89.7 89.4 Accrued insurance obligations 21.8 21.4 Accrued taxes other than income 26.6 25.3 Other 43.9 37.7 Accounts payable and accrued liabilities $ 456.9 $ 513.4

Long-Term Debt (Tables)

Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Summary of Long-Term Debt	Long-term debt consisted of the following: December 31, (Millions of dollars) 2018 2017 6.00% senior notes due 2023 (net of unamortized discount of $4.1 at 2018 and $5.0 at 2017) $ 495.9 $ 495.0 5.625% senior notes due 2027 (net of unamortized discount of $3.1 at 2018 and $3.5 at 2017) 296.9 296.5 Term loan due 2020 (effective rate of 5.0% at 2018 and 4.15% at 2017 ) 72.0 92.0 Capitalized lease obligations, vehicles, due through 2022 2.3 2.4 Unamortized debt issuance costs (3.8 ) (5.1 ) Total long-term debt 863.3 880.8 Less current maturities 21.2 19.9 Total long-term debt, net of current $ 842.1 $ 860.9

Asset Retirement Obligations _2

Asset Retirement Obligations (ARO) (Tables)	12 Months Ended
	Dec. 31, 2018
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) 2018 2017 Balance at beginning of period $ 28.2 $ 26.2 Accretion expense 2.0 1.8 Settlements of liabilities (0.3 ) (0.3 ) Liabilities incurred 0.8 0.5 Balance at end of period $ 30.7 $ 28.2

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Summary of Effective Income Tax Rates	The components of income from continuing operations before income taxes for each of the three years ended December 31, 2018 and income tax expense (benefit) attributable thereto were as follows: Years Ended December 31, (Millions of dollars) 2018 2017 2016 Income (loss) from continuing operations before income taxes $ 273.9 $ 240.1 $ 352.1 Income tax expense (benefit) Federal - Current $ 18.4 39.2 74.9 Federal - Deferred 31.0 (50.7 ) 38.8 State - Current and deferred 10.9 6.3 16.9 Total $ 60.3 $ (5.2 ) $ 130.6
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) 2018 2017 2016 Income tax expense based on the U.S. statutory tax rate $ 57.5 $ 84.0 $ 123.2 State income taxes, net of federal benefit 8.3 3.0 11.5 Effect of U.S. tax law change — (88.9 ) — Other, net (5.5 ) (3.3 ) (4.1 ) Total $ 60.3 $ (5.2 ) $ 130.6
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, 2018 and 2017 showing the tax effects of significant temporary differences is as follows: December 31, (Millions of dollars) 2018 2017 Deferred tax assets Property costs and asset retirement obligations $ 3.3 $ 2.8 Employee benefits 6.3 4.4 Other deferred tax assets 2.6 3.5 Total gross deferred tax assets 12.2 10.7 Deferred tax liabilities Accumulated depreciation and amortization (171.6 ) (142.1 ) State deferred taxes (25.9 ) (18.9 ) Other deferred tax liabilities (6.9 ) (3.9 ) Total gross deferred tax liabilities (204.4 ) (164.9 ) Net deferred tax liabilities $ (192.2 ) $ (154.2 )
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, 2018 and 2017 is shown in the following table. Year Ended December 31, (Millions of dollars) 2018 2017 Balance at January 1 $ 4.4 $ 7.9 Additions for tax positions related to prior years — 4.4 Additions for tax positions related to current year 0.2 — Settlements with taxing authorities (3.9 ) (5.5 ) Expiration of statutes of limitation — (2.4 ) Balance at December 31 $ 0.7 $ 4.4

Incentive Plans (Tables)

Incentive Plans (Tables)	12 Months Ended
	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
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. All expense prior to August 30, 2013 was incurred under the 2007 Plan and the 2012 Plan while all amounts after August 30, 2013 were incurred in the MUSA 2013 Plan and the Directors Plan. December 31, (Millions of dollars) 2018 2017 2016 Compensation charged against income before income tax benefit $ 9.2 $ 7.5 $ 9.3 Related income tax benefit recognized in income $ 1.9 $ 2.6 $ 3.3
Summary of Changes in Stock Options Outstanding	Changes in options outstanding for Company employees during the period from December 31, 2015 to December 31, 2018 are presented in the following table: Number of Shares Average Exercise Price Outstanding at December 31, 2015 465,756 $ 42.22 Granted at FMV 96,500 59.11 Vested and issued (126,969 ) 34.48 Forfeited (14,350 ) 58.28 Outstanding at December 31, 2016 420,937 47.88 Granted at FMV 114,800 65.75 Exercised (43,887 ) 37.41 Forfeited (25,950 ) 63.63 Outstanding at December 31, 2017 465,900 52.39 Granted at FMV 97,600 71.07 Exercised (220,938 ) 39.48 Forfeited (32,200 ) 69.21 Outstanding at December 31, 2018 310,362 $ 65.71 Exercisable at December 31, 2016 218,937 $ 38.32 Exercisable at December 31, 2017 254,375 $ 42.80 Exercisable at December 31, 2018 100,662 $ 64.17
Summary of Additional Stock Option Information	Additional information about stock options outstanding at December 31, 2018 is shown below: Options Outstanding Options Exercisable Range of Exercise Prices per Option No. of Options Avg. Life Remaining in Years Aggregate Intrinsic Value No. of Options Avg. Life Remaining in Years Aggregate Intrinsic Value $32.53 to $39.99 7,062 3.2 $ 280,472 7,062 3.2 $ 280,472 $40.00 to $59.99 74,800 4.1 1,311,244 35,500 4.1 622,315 $60.00 to $69.99 94,000 5.1 1,023,660 — 0.0 — $70.00 to $79.99 134,500 4.8 776,363 58,100 3.0 352,667 310,362 4.7 $ 3,391,739 100,662 3.4 $ 1,255,454
Murphy Oil Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Summary of Valuation Assumptions	Following are the assumptions used originally by Murphy Oil to value the original awards. Years Ended December 31, 2012 and 2011 Fair value per option grant 12.37 - 20.34 Assumptions Dividend yield 1.80% - 2.27% Expected volatility 37.00% - 39.62% Risk-free interest rate 0.55% - 2.10% Expected life 4.00 yrs. - 5.20 yrs.
MUSA 2013 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Summary of Valuation Assumptions	Following are the assumptions used by the Company to value the original awards: Year Ended December 31, 2018 2017 2016 Fair value per option grant $ 17.32 $ 15.45 $ 16.08 Assumptions Dividend yield — — — Expected volatility 27.0 % 26.0 % 26.1 % Risk-free interest rate 2.43 % 1.65 % 1.26 % Expected life 3.9 years 4.2 years 5.7 years
Restricted Stock Units | MUSA 2013 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Summary of Restricted Stock Unit Activity	(Number of units) Employee RSU's Outstanding at December 31, 2015 356,300 Granted at FMV 74,325 Vested and issued (142,392 ) Forfeited (18,888 ) Outstanding at December 31, 2016 269,345 Granted at FMV 111,471 Vested and issued (60,688 ) Forfeited (61,112 ) Outstanding at December 31, 2017 259,016 Granted FMV 69,179 Vested and issued (96,815 ) Forfeited (37,902 ) Outstanding at December 31, 2018 193,478
Restricted Stock Units | 2013 Stock Plan For Non-Employee Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Summary of Restricted Stock Unit Activity	(Number of units) Director RSU's Outstanding at December 31, 2015 63,774 Granted at FMV 19,900 Vested and issued (34,332 ) Forfeited — Outstanding at December 31, 2016 49,342 Granted at FMV 15,948 Vested and issued (19,944 ) Forfeited — Outstanding at December 31, 2017 45,346 Granted at FMV 10,921 Vested and issued (15,250 ) Forfeited — Outstanding at December 31, 2018 41,017
Performance Units | MUSA 2013 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Summary of Restricted Stock Unit Activity	(Number of units) Employee PSU's Outstanding at December 31, 2015 102,394 Granted 53,300 Vested and issued — Forfeited (7,954 ) Outstanding at December 31, 2016 147,740 Granted 53,800 Vested and issued (60,816 ) Forfeited (16,000 ) Outstanding at December 31, 2017 124,724 Granted 66,284 Vested and issued (51,296 ) Forfeited (15,300 ) Outstanding at December 31, 2018 124,412

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2018
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, 2018 , 2017 and 2016 (in millions, except per share amounts): Years ended December 31, (Millions of dollars except per share amounts) 2018 2017 2016 Earnings per common share: Net income per share - basic Net income attributable to common stockholders $ 213.6 $ 245.3 $ 221.5 Weighted average common shares outstanding (in thousands) 32,674 35,816 39,269 Earnings per common share $ 6.54 $ 6.85 $ 5.64 Earnings per common share - assuming dilution: Net income per share - diluted Net income attributable to common stockholders $ 213.6 $ 245.3 $ 221.5 Weighted average common shares outstanding (in thousands) 32,674 35,816 39,269 Common equivalent shares: Share-based awards 309 340 377 Weighted average common shares outstanding - assuming dilution (in thousands) 32,983 36,156 39,646 Earnings per common share assuming dilution $ 6.48 $ 6.78 $ 5.59

Other Financial Information (Ta

Other Financial Information (Tables)	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary of Changes in Operating Working Capital	CHANGES IN WORKING CAPITAL - (Millions of dollars) 2018 2017 2016 Accounts receivable $ 86.6 $ (41.7 ) $ (47.2 ) Inventories (39.0 ) (16.3 ) 2.1 Prepaid expenses and other current assets 11.4 (5.2 ) 13.7 Accounts payable and accrued liabilities (56.7 ) 26.9 83.4 Income taxes payable — (0.6 ) 1.7 Net decrease (increase) in noncash operating working capital $ 2.3 $ (36.9 ) $ 53.7

Assets and Liabilities Measur_2

Assets and Liabilities Measure at Fair Value (Tables)	12 Months Ended
	Dec. 31, 2018
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, 2018 and 2017 . 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, 2018 December 31, 2017 Carrying Carrying (Millions of dollars) Amount Fair Value Amount Fair Value Financial liabilities Current and long-term debt $ (863.3 ) $ (866.7 ) $ (880.8 ) $ (904.9 )

Business Segments (Tables)

Business Segments (Tables)	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Summary of Information by Business Segment	Segment Information Corporate and (Millions of dollars) Marketing Other Assets 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 Year ended December 31, 2017 Segment income (loss) $ 295.3 (50.0 ) $ 245.3 Revenues from external customers 12,826.2 0.4 12,826.6 Interest income — 1.3 1.3 Interest expense (0.1 ) (46.6 ) (46.7 ) Income tax expense (benefit) (2.9 ) (2.3 ) (5.2 ) Significant noncash charges (credits) Depreciation and amortization 110.5 6.4 116.9 Accretion of asset retirement obligations 1.8 — 1.8 Deferred and noncurrent income taxes (benefits) (61.3 ) 10.9 (50.4 ) Additions to property, plant and equipment 234.0 39.7 273.7 Total assets at year-end $ 2,023.4 307.6 $ 2,331.0 Year ended December 31, 2016 Segment income (loss) $ 249.8 (28.3 ) $ 221.5 Revenues from external customers 11,594.3 0.3 11,594.6 Interest income — 0.6 0.6 Interest expense (0.1 ) (39.6 ) (39.7 ) Income tax expense (benefit) 147.2 (16.6 ) 130.6 Significant noncash charges (credits) Depreciation and amortization 92.2 6.4 98.6 Accretion of asset retirement obligations 1.6 — 1.6 Deferred and noncurrent income taxes (benefits) 51.3 (10.9 ) 40.4 Additions to property, plant and equipment 239.1 24.8 263.9 Total assets at year-end $ 1,858.0 230.7 $ 2,088.7

Guarantor Subsidiaries (Tables)

Guarantor Subsidiaries (Tables)	12 Months Ended
	Dec. 31, 2018
Guarantor Subsidiaries [Abstract]
Consolidating Balance Sheet	CONSOLIDATING BALANCE SHEET (Millions of dollars) December 31, 2018 Assets Parent Company Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Current assets Cash and cash equivalents $ — $ 184.0 $ 0.5 $ — $ — $ 184.5 Accounts receivable—trade, less allowance for doubtful accounts of $1.1 in 2018 — 138.8 — — — 138.8 Inventories, at lower of cost or market — 221.5 — — — 221.5 Prepaid expenses and other current assets — 25.1 0.2 — — 25.3 Total current assets — 569.4 0.7 — — 570.1 Property, plant and equipment, at cost less accumulated depreciation and amortization of $974.2 in 2018 — 1,745.9 2.3 — — 1,748.2 Investments in subsidiaries 2,437.0 144.4 — — (2,581.4 ) — Other assets — 42.5 — — — 42.5 Total assets $ 2,437.0 $ 2,502.2 $ 3.0 $ — $ (2,581.4 ) $ 2,360.8 Liabilities and Stockholders' Equity Current liabilities Current maturities of long-term debt $ — $ 21.2 $ — $ — $ — $ 21.2 Inter-company accounts payable (0.1 ) 203.0 (48.6 ) (154.3 ) — — Trade accounts payable and accrued liabilities — 456.9 — — — 456.9 Total current liabilities (0.1 ) 681.1 (48.6 ) (154.3 ) — 478.1 Long-term debt, including capitalized lease obligations — 842.1 — — — 842.1 Deferred income taxes — 192.2 — — — 192.2 Asset retirement obligations — 30.7 — — — 30.7 Deferred credits and other liabilities — 10.4 — — — 10.4 Total liabilities (0.1 ) 1,756.5 (48.6 ) (154.3 ) — 1,553.5 Stockholders' Equity Preferred Stock, par $0.01 (authorized 20,000,000 shares, none outstanding) — — — — — — Common Stock, par $0.01 (authorized 200,000,000 shares, 46,767,164 shares issued at December 31, 2018) 0.5 — 0.1 — (0.1 ) 0.5 Treasury stock (14,505,681 shares held at December 31, 2018) (940.3 ) — — — — (940.3 ) Additional paid in capital (APIC) 1,195.1 572.8 52.0 87.5 (1,368.4 ) 539.0 Retained earnings 2,181.8 172.9 (0.5 ) 66.8 (1,212.9 ) 1,208.1 Total stockholders' equity 2,437.1 745.7 51.6 154.3 (2,581.4 ) 807.3 Total liabilities and stockholders' equity $ 2,437.0 $ 2,502.2 $ 3.0 $ — $ (2,581.4 ) $ 2,360.8 CONSOLIDATING BALANCE SHEET (Millions of dollars) December 31, 2017 Assets Parent Company Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Current assets Cash and cash equivalents $ — $ 169.9 $ 0.1 $ — $ — $ 170.0 Accounts receivable—trade, less allowance for doubtful accounts of $1.1 in 2017 — 225.2 — — — 225.2 Inventories, at lower of cost or market — 182.5 — — — 182.5 Prepaid expenses and other current assets — 36.5 — — — 36.5 Total current assets — 614.1 0.1 — — 614.2 Property, plant and equipment, at cost less accumulated depreciation and amortization of $874.7 in 2017 — 1,678.3 1.2 — — 1,679.5 Investments in subsidiaries 2,223.4 144.9 — — (2,368.3 ) — Other assets — 37.3 — — — 37.3 Total assets $ 2,223.4 $ 2,474.6 $ 1.3 $ — $ (2,368.3 ) $ 2,331.0 Liabilities and Stockholders' Equity Current liabilities Current maturities of long-term debt $ — $ 19.9 $ — $ — $ — $ 19.9 Inter-company accounts payable 829.2 (624.1 ) (50.8 ) (154.3 ) — — Trade accounts payable and accrued liabilities — 513.4 — — — 513.4 Total current liabilities 829.2 (90.8 ) (50.8 ) (154.3 ) — 533.3 Long-term debt, including capitalized lease obligations — 860.9 — — — 860.9 Deferred income taxes — 154.2 — — — 154.2 Asset retirement obligations — 28.2 — — — 28.2 Deferred credits and other liabilities — 16.0 — — — 16.0 Total liabilities 829.2 968.5 (50.8 ) (154.3 ) — 1,592.6 Stockholders' Equity Preferred Stock, par $0.01 (authorized 20,000,000 shares, none outstanding) — — — — — — Common Stock, par $0.01 (authorized 200,000,000 shares, 46,767,164 shares issued at December 31, 2017) 0.5 — 0.1 — (0.1 ) 0.5 Treasury stock (12,675,630 shares held at December 31, 2017) (806.5 ) — — — — (806.5 ) Additional paid in capital (APIC) 1,205.7 573.1 52.0 87.5 (1,368.4 ) 549.9 Retained earnings 994.5 933.0 — 66.8 (999.8 ) 994.5 Total stockholders' equity 1,394.2 1,506.1 52.1 154.3 (2,368.3 ) 738.4 Total liabilities and stockholders' equity $ 2,223.4 $ 2,474.6 $ 1.3 $ — $ (2,368.3 ) $ 2,331.0
Consolidating Income Statement	CONSOLIDATING INCOME STATEMENT (Millions of dollars) Year ended December 31, 2018 Operating Revenues Parent Company Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Petroleum product sales $ — $ 11,858.4 $ — $ — $ — $ 11,858.4 Merchandise sales — 2,423.0 — — — 2,423.0 Other operating revenues — 81.5 — — — 81.5 Total operating revenues — 14,362.9 — — — 14,362.9 Operating expenses Petroleum product cost of goods sold — 11,251.1 — — — 11,251.1 Merchandise cost of goods sold — 2,022.5 — — — 2,022.5 Station and other operating expenses — 541.3 — — — 541.3 Depreciation and amortization — 134.0 — — — 134.0 Selling, general and administrative — 136.2 — — — 136.2 Accretion of asset retirement obligations — 2.0 — — — 2.0 Total operating expenses — 14,087.1 — — — 14,087.1 Net settlement proceeds — 50.4 — — — 50.4 Gain (loss) on sale of assets — (1.1 ) — — — (1.1 ) Income from operations — 325.1 — — — 325.1 Other income (expense) Interest income — 1.5 — — — 1.5 Interest expense — (52.9 ) — — — (52.9 ) Other nonoperating income/expense 973.7 (972.9 ) (0.6 ) — — 0.2 Total other income (expense) 973.7 (1,024.3 ) (0.6 ) — — (51.2 ) Income from continuing operations before income taxes 973.7 (699.2 ) (0.6 ) — — 273.9 Income tax expense (benefit) — 60.4 (0.1 ) — — 60.3 Income (loss) 973.7 (759.6 ) (0.5 ) — — 213.6 Equity earnings in affiliates, net of tax 213.6 (0.5 ) — — (213.1 ) — Net Income (Loss) $ 1,187.3 $ (760.1 ) $ (0.5 ) $ — $ (213.1 ) $ 213.6 CONSOLIDATING INCOME STATEMENT (Millions of dollars) Year ended December 31, 2017 Operating Revenues Parent Company Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Petroleum product sales $ — $ 10,287.9 $ — $ — $ — $ 10,287.9 Merchandise sales — 2,372.7 — — — 2,372.7 Ethanol sales and other — 166.0 — — — 166.0 Total operating revenues — 12,826.6 — — — 12,826.6 Operating Expenses Petroleum product cost of goods sold — 9,773.2 — — — 9,773.2 Merchandise cost of goods sold — 1,991.4 — — — 1,991.4 Station and other operating expenses — 514.9 — — — 514.9 Depreciation and amortization — 116.9 — — — 116.9 Selling, general and administrative — 141.2 — — — 141.2 Accretion of asset retirement obligations — 1.8 — — — 1.8 Total operating expenses — 12,539.4 — — — 12,539.4 Gain (loss) on sale of assets — (3.9 ) — — — (3.9 ) Income from operations — 283.3 — — — 283.3 Other income (expense) Interest income — 1.3 — — — 1.3 Interest expense — (46.7 ) — — — (46.7 ) Other nonoperating income — 2.2 — — — 2.2 Total other income (expense) — (43.2 ) — — — (43.2 ) Income from continuing operations before income taxes — 240.1 — — — 240.1 Income tax expense (benefit) — (5.2 ) — — — (5.2 ) Income from continuing operations — 245.3 — — — 245.3 Equity earnings in affiliates, net of tax 245.3 — — — (245.3 ) — Net Income $ 245.3 $ 245.3 $ — $ — $ (245.3 ) $ 245.3 CONSOLIDATING INCOME STATEMENT (Millions of dollars) Year ended December 31, 2016 Operating Revenues Parent Company Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Petroleum product sales $ — $ 9,070.6 $ — $ — $ — $ 9,070.6 Merchandise sales — 2,338.6 — — — 2,338.6 Ethanol sales and other — 185.4 — — — 185.4 Total operating revenues — 11,594.6 — — — 11,594.6 Operating expenses Petroleum product cost of goods sold — 8,604.0 — — — 8,604.0 Merchandise cost of goods sold — 1,974.5 — — — 1,974.5 Station and other operating expenses — 493.3 — — — 493.3 Depreciation and amortization — 98.6 — — — 98.6 Selling, general and administrative — 122.7 — — — 122.7 Accretion of asset retirement obligations — 1.6 — — — 1.6 Total operating expenses — 11,294.7 — — — 11,294.7 Gain (loss) on sale of assets — 88.2 — — — 88.2 Income from operations — 388.1 — — — 388.1 Other income (expense) Interest income — 0.6 — — — 0.6 Interest expense — (39.7 ) — — — (39.7 ) Other nonoperating income — 3.1 — — — 3.1 Total other income (expense) — (36.0 ) — — — (36.0 ) Income from continuing operations before income taxes — 352.1 — — — 352.1 Income tax expense (benefit) — 130.6 — — — 130.6 Income from continuing operations — 221.5 — — — 221.5 Equity earnings in affiliates, net of tax 221.5 — — — (221.5 ) — Net Income $ 221.5 $ 221.5 $ — $ — $ (221.5 ) $ 221.5
Consolidating Statement of Cash Flow	CONSOLIDATING STATEMENT OF CASH FLOWS (Millions of dollars) Year ended December 31, 2018 Operating Activities Parent Company Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Net income (loss) $ 1,187.3 $ (760.1 ) $ (0.5 ) $ — $ (213.1 ) $ 213.6 Adjustments to reconcile net income (loss) to net cash provided by operating activities Depreciation and amortization — 134.0 — — — 134.0 Deferred and noncurrent income tax charges (benefits) — 37.9 — — — 37.9 Accretion of asset retirement obligations — 2.0 — — — 2.0 (Gain) loss from sale of assets — 1.1 — — — 1.1 Net decrease (increase) in noncash operating working capital — 2.4 (0.1 ) — — 2.3 Equity in earnings (213.6 ) 0.5 — — 213.1 — Other operating activities - net — 7.8 — — — 7.8 Net cash provided by (required by) operating activities 973.7 (574.4 ) (0.6 ) — — 398.7 Investing Activities Property additions — (203.1 ) (1.2 ) — — (204.3 ) Proceeds from sale of assets — 1.2 — — — 1.2 Other investing activities - net — (6.0 ) — — — (6.0 ) Net cash provided by (required by) investing activities — (207.9 ) (1.2 ) — — (209.1 ) Financing Activities Purchase of treasury stock (144.4 ) — — — — (144.4 ) Repayments of long-term debt — (21.3 ) — — — (21.3 ) Amounts related to share-based compensation — (9.4 ) — — — (9.4 ) Net distributions to parent (829.3 ) 827.1 2.2 — — — Net cash provided by (required by) financing activities (973.7 ) 796.4 2.2 — — (175.1 ) Net change in cash and cash equivalents — 14.1 0.4 — — 14.5 Cash, cash equivalents, and restricted cash at January 1 — 169.9 0.1 — — 170.0 Cash, cash equivalents, and restricted cash at December 31 $ — $ 184.0 $ 0.5 $ — $ — $ 184.5 CONSOLIDATING STATEMENT OF CASH FLOWS (Millions of dollars) Year ended December 31, 2017 Operating Activities Parent Company Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Net income (loss) $ 245.3 $ 245.3 $ — $ — $ (245.3 ) $ 245.3 Adjustments to reconcile net income (loss) to net cash provided by operating activities Depreciation and amortization — 116.9 — — — 116.9 Deferred and noncurrent income tax charges (credits) — (50.4 ) — — — (50.4 ) Accretion of asset retirement obligations — 1.8 — — — 1.8 (Gains) loss from sale of assets — 3.9 — — — 3.9 Net decrease (increase) in noncash operating working capital — (36.9 ) — — — (36.9 ) Equity in earnings (245.3 ) — — — 245.3 — Other operating activities - net — 3.0 — — — 3.0 Net cash provided by (required by) operating activities — 283.6 — — — 283.6 Investing Activities Property additions — (257.1 ) (1.2 ) — — (258.3 ) Proceeds from sale of assets — 0.9 — — — 0.9 Other investing activities - net — (4.7 ) — — — (4.7 ) Net cash provided by (required by) investing activities — (260.9 ) (1.2 ) — — (262.1 ) Financing Activities Purchase of treasury stock (206.0 ) — — — — (206.0 ) Repayments of long-term debt — (131.4 ) — — — (131.4 ) Additions to long-term debt — 338.8 — — — 338.8 Debt issuance costs — (1.1 ) — — — (1.1 ) Amounts related to share-based compensation — (5.6 ) — — — (5.6 ) Net distributions to parent 206.0 (207.3 ) 1.3 — — — Net cash provided by (required by) financing activities — (6.6 ) 1.3 — — (5.3 ) Net change in cash and cash equivalents — 16.1 0.1 — — 16.2 Cash, cash equivalents, and restricted cash at January 1 — 153.8 — — — 153.8 Cash, cash equivalents, and restricted cash at December 31 $ — $ 169.9 $ 0.1 $ — $ — $ 170.0 CONSOLIDATING STATEMENT OF CASH FLOWS (Millions of dollars) Year ended December 31, 2016 Operating Activities Parent Company Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Net income (loss) $ 221.5 $ 221.5 $ — $ — $ (221.5 ) $ 221.5 Adjustments to reconcile net income (loss) to net cash provided by operating activities Depreciation and amortization — 98.6 — — — 98.6 Deferred and noncurrent income tax charges (credits) — 40.4 — — — 40.4 Accretion of asset retirement obligations — 1.6 — — — 1.6 (Gains) loss from sale of assets — (88.2 ) — — — (88.2 ) Net decrease (increase) in noncash operating working capital — 53.7 — — — 53.7 Equity in earnings (221.5 ) — — — 221.5 — Other operating activities - net — 9.8 — — — 9.8 Net cash provided by (required by) operating activities — 337.4 — — — 337.4 Investing Activities Property additions — (262.1 ) — — — (262.1 ) Proceeds from sale of assets — 85.3 — — — 85.3 Changes in restricted cash — 68.6 — — — 68.6 Other investing activities - net — (29.0 ) — — — (29.0 ) Other — 2.4 — — — 2.4 Net cash provided by (required by) investing activities — (134.8 ) — — — (134.8 ) Financing Activities Purchase of treasury stock (323.3 ) — — — — (323.3 ) Repayments of long-term debt — (20.4 ) — — — (20.4 ) Additions to long-term debt — 200.0 — — — 200.0 Debt issuance costs — (3.2 ) — — — (3.2 ) Amounts related to share-based compensation — (4.2 ) — — — (4.2 ) Net distributions to parent 323.3 (323.3 ) — — — — Net cash provided by (required by) financing activities — (151.1 ) — — — (151.1 ) Net change in cash and cash equivalents — 51.5 — — — 51.5 Cash, cash equivalents and restricted cash at January 1 — 102.3 — — — 102.3 Cash, cash equivalents and restricted cash at December 31 $ — $ 153.8 $ — $ — $ — $ 153.8 Reconciliation of Cash, Cash Equivalents and Restricted Cash Cash and cash equivalents at beginning of period $ — $ 33.7 $ — $ — $ — $ 33.7 Restricted cash at beginning of period — 68.6 — — — 68.6 Cash, cash equivalents and restricted cash at beginning of period $ — $ 102.3 $ — $ — $ — $ 102.3 Cash and cash equivalents at end of period $ — $ 153.8 $ — $ — $ — $ 153.8 Restricted cash at end of period — — — — — $ — Cash, cash equivalents and restricted cash at end of period $ — $ 153.8 $ — $ — $ — $ 153.8
Consolidating Statement of Changes in Equity	CONSOLIDATING STATEMENT OF CHANGES IN EQUITY (Millions of dollars) Year ended December 31, 2018 Statement of Stockholders' Equity Parent Company Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Common Stock Balance as of December 31, 2017 $ 0.5 $ — $ 0.1 $ — $ (0.1 ) $ 0.5 Issuance of common stock — — — — — — Balance as of December 31, 2018 $ 0.5 $ — $ 0.1 $ — $ (0.1 ) $ 0.5 Treasury Stock Balance as of December 31, 2017 $ (806.5 ) $ — $ — $ — $ — $ (806.5 ) Issuance of common stock 10.6 — — — — 10.6 Repurchase of common stock (144.4 ) — — — — (144.4 ) Balance as of December 31, 2018 $ (940.3 ) $ — $ — $ — $ — $ (940.3 ) APIC Balance as of December 31, 2017 $ 1,205.7 $ 573.1 $ 52.0 $ 87.5 $ (1,368.4 ) $ 549.9 Issuance of common stock (10.6 ) — — — — (10.6 ) Amounts related to share-based compensation — (9.4 ) — — — (9.4 ) Share-based compensation expense — 9.1 — — — 9.1 Balance as of December 31, 2018 $ 1,195.1 $ 572.8 $ 52.0 $ 87.5 $ (1,368.4 ) $ 539.0 Retained Earnings Balance as of December 31, 2017 $ 994.5 $ 933.0 $ — $ 66.8 $ (999.8 ) $ 994.5 Net income 1,187.3 (760.1 ) (0.5 ) — (213.1 ) 213.6 Balance as of December 31, 2018 $ 2,181.8 $ 172.9 $ (0.5 ) $ 66.8 $ (1,212.9 ) $ 1,208.1 CONSOLIDATING STATEMENTS OF CHANGES IN EQUITY (Millions of dollars) Year ended December 31, 2017 Statement of Stockholders' Equity Parent Company Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Common Stock Balance as of December 31, 2016 $ 0.5 $ — $ 0.1 $ — $ (0.1 ) $ 0.5 Issuance of common stock — — — — — — Balance as of December 31, 2017 $ 0.5 $ — $ 0.1 $ — $ (0.1 ) $ 0.5 Treasury Stock Balance as of December 31, 2016 $ (608.0 ) $ — $ — $ — $ — $ (608.0 ) Issuance of common stock 7.5 — — — — 7.5 Repurchase of common stock (206.0 ) — — — — (206.0 ) Balance as of December 31, 2017 $ (806.5 ) $ — $ — $ — $ — $ (806.5 ) APIC Balance as of December 31, 2016 $ 1,213.1 $ 571.1 $ 52.0 $ 87.5 $ (1,368.4 ) $ 555.3 Issuance of common stock (7.4 ) — — — — (7.4 ) Amounts related to share-based compensation — (5.6 ) — — — (5.6 ) Reclassification of equity — — — — — — Share-based compensation expense — 7.6 — — — 7.6 Balance as of December 31, 2017 $ 1,205.7 $ 573.1 $ 52.0 $ 87.5 $ (1,368.4 ) $ 549.9 Retained Earnings Balance as of December 31, 2016 $ 749.2 $ 687.7 $ — $ 66.8 $ (754.5 ) $ 749.2 Net income 245.3 245.3 — — (245.3 ) 245.3 Balance as of December 31, 2017 $ 994.5 $ 933.0 $ — $ 66.8 $ (999.8 ) $ 994.5 CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Millions of dollars) Year ended December 31, 2016 Statement of Stockholders' Equity Parent Company Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Common Stock Balance as of December 31, 2015 $ 0.5 $ — $ 0.1 $ — $ (0.1 ) $ 0.5 Issuance of common stock — — — — — — Balance as of December 31, 2016 $ 0.5 $ — $ 0.1 $ — $ (0.1 ) $ 0.5 Treasury Stock Balance as of December 31, 2015 $ (294.1 ) $ — $ — $ — $ — $ (294.1 ) Issuance of common stock 9.4 — — — — 9.4 Repurchase of common stock (323.3 ) — — — — (323.3 ) Balance as of December 31, 2016 $ (608.0 ) $ — $ — $ — $ — $ (608.0 ) APIC Balance as of December 31, 2015 $ 1,222.5 $ 564.5 $ 52.0 $ 87.5 $ (1,368.4 ) $ 558.1 Issuance of common stock (9.4 ) — — — — (9.4 ) Amounts related to share-based compensation — (2.7 ) — — — (2.7 ) Share-based compensation expense — 9.3 — — — 9.3 Balance as of December 31, 2016 $ 1,213.1 $ 571.1 $ 52.0 $ 87.5 $ (1,368.4 ) $ 555.3 Retained Earnings Balance as of December 31, 2015 $ 527.7 $ 466.2 $ — $ 66.8 $ (533.0 ) $ 527.7 Net income 221.5 221.5 — — (221.5 ) 221.5 Balance as of December 31, 2016 $ 749.2 $ 687.7 $ — $ 66.8 $ (754.5 ) $ 749.2

Supplemental Quarterly Inform_2

Supplemental Quarterly Information (Tables)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	First Second Third Fourth (Millions of dollars except per share amounts) Quarter Quarter Quarter Quarter Year Year Ended December 31, 2018 Sales and other operating revenues $ 3,244.2 $ 3,829.0 $ 3,788.0 $ 3,501.7 $ 14,362.9 Income (loss) from continuing operations before income taxes $ 47.3 $ 69.1 $ 57.0 $ 100.5 $ 273.9 Income (loss) from continuing operations $ 39.3 $ 51.8 $ 45.0 $ 77.5 $ 213.6 Net income (loss) $ 39.3 $ 51.8 $ 45.0 $ 77.5 $ 213.6 Income (loss) from continuing operations (per Common share) Basic $ 1.17 $ 1.59 $ 1.40 $ 2.40 $ 6.54 Diluted $ 1.16 $ 1.58 $ 1.38 $ 2.38 $ 6.48 Net income (loss) (per Common share) Basic $ 1.17 $ 1.59 $ 1.40 $ 2.40 $ 6.54 Diluted $ 1.16 $ 1.58 $ 1.38 $ 2.38 $ 6.48 Year Ended December 31, 2017 Sales and other operating revenues $ 2,999.6 $ 3,211.2 $ 3,236.3 $ 3,379.5 $ 12,826.6 Income (loss) from continuing operations before income taxes $ (9.8 ) $ 89.9 $ 108.8 $ 51.2 $ 240.1 Income (loss) from continuing operations $ (3.0 ) $ 55.5 $ 67.9 $ 124.9 $ 245.3 Net income (loss) $ (3.0 ) $ 55.5 $ 67.9 $ 124.9 $ 245.3 Income (loss) from continuing operations (per Common share) Basic $ (0.08 ) $ 1.52 $ 1.92 $ 3.62 $ 6.85 Diluted $ (0.08 ) $ 1.51 $ 1.90 $ 3.58 $ 6.78 Net income (loss) (per Common share) Basic $ (0.08 ) $ 1.52 $ 1.92 $ 3.62 $ 6.85 Diluted $ (0.08 ) $ 1.51 $ 1.90 $ 3.58 $ 6.78

Description of Business and B_2

Description of Business and Basis of Presentation (Details)	Aug. 31, 2013	Aug. 30, 2013	Dec. 31, 2018statestore
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 | state			26
Number of stores | store			1,472

Significant Accounting Polici_3

Significant Accounting Policies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Excise taxes	$ 1,838.9	$ 1,973.1	$ 1,961.5
Interest costs capitalized	$ 2.2	$ 3.8
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
Marketing Facilities | Minimum
Property, Plant and Equipment [Line Items]
Depreciable life (in years)	3 years
Marketing Facilities | 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	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Revenue	$ 3,501.7	$ 3,788	$ 3,829	$ 3,244.2	$ 3,379.5	$ 3,236.3	$ 3,211.2	$ 2,999.6	$ 14,362.9	$ 12,826.6	$ 11,594.6
Merchandise sales
Disaggregation of Revenue [Line Items]
Revenue									2,423	2,372.7	2,338.6
Operating Segment
Disaggregation of Revenue [Line Items]
Revenue									14,362.3	160.3	11,594.3
Operating Segment | Petroleum product sales (at retail)
Disaggregation of Revenue [Line Items]
Revenue									10,459.2	9,041.5	8,087.4
Operating Segment | Petroleum product sales (at wholesale)
Disaggregation of Revenue [Line Items]
Revenue									1,399.2	1,246.4	980.5
Operating Segment | Other Petroleum product sales
Disaggregation of Revenue [Line Items]
Revenue									0	0	2.7
Operating Segment | Total petroleum product sales
Disaggregation of Revenue [Line Items]
Revenue									11,858.4	10,287.9	9,070.6
Operating Segment | Merchandise sales
Disaggregation of Revenue [Line Items]
Revenue									2,423	2,372.6	2,338.6
Operating Segment | Renewable Identification Numbers (RINs) sales
Disaggregation of Revenue [Line Items]
Revenue									75.2		181.2
Operating Segment | Other
Disaggregation of Revenue [Line Items]
Revenue									5.7		3.9
Operating Segment | Marketing
Disaggregation of Revenue [Line Items]
Revenue										12,826.2
Operating Segment | Marketing | Other
Disaggregation of Revenue [Line Items]
Revenue										5.4
Corporate and Other Assets
Disaggregation of Revenue [Line Items]
Revenue									$ 0.6	$ 0.4	$ 0.3

Revenues (Narrative) (Details)

Revenues (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Revenue	$ 3,501,700	$ 3,788,000	$ 3,829,000	$ 3,244,200	$ 3,379,500	$ 3,236,300	$ 3,211,200	$ 2,999,600	$ 14,362,900	$ 12,826,600	$ 11,594,600
Earned rewards, expiration period									90 days
Trade accounts receivable	138,800				225,200				$ 138,800	225,200
Receivables related to contracts with customers
Disaggregation of Revenue [Line Items]
Trade accounts receivable	$ 79,400				$ 145,600				79,400	$ 145,600
Petroleum product sales (at retail) | Difference between Revenue Guidance in Effect before and after Topic 606
Disaggregation of Revenue [Line Items]
Revenue									25,400
Petroleum product sales (at wholesale) | Difference between Revenue Guidance in Effect before and after Topic 606
Disaggregation of Revenue [Line Items]
Revenue									171,200
Petroleum product sales | Difference between Revenue Guidance in Effect before and after Topic 606
Disaggregation of Revenue [Line Items]
Revenue									$ 196,500
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 years

Inventories (Summary Of Invento

Inventories (Summary Of Inventory) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Inventory Disclosure [Abstract]
Finished products - FIFO basis	$ 219,400	$ 231,900
Less LIFO reserve - finished products	(115,500)	(167,200)
Finished products - LIFO basis	103,900	64,700
Store merchandise for resale	107,200	104,800
Materials and supplies	10,400	13,000
Total inventories	$ 221,500	$ 182,500

Property, Plant and Equipment_2

Property, Plant and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Net	$ 1,748,200	$ 1,679,500
Depreciation expense	133,000	115,000	$ 97,000
Land
Property, Plant and Equipment [Line Items]
Cost	591,900	586,500
Net	591,900	586,500
Pipeline and terminal facilities
Property, Plant and Equipment [Line Items]
Cost	73,100	72,000
Net	41,600	43,000
Retail gasoline stations
Property, Plant and Equipment [Line Items]
Cost	1,890,600	1,752,600
Net	1,018,500	968,900
Buildings
Property, Plant and Equipment [Line Items]
Cost	55,000	54,600
Net	41,800	42,900
Other
Property, Plant and Equipment [Line Items]
Cost	111,800	88,500
Net	$ 54,400	$ 38,200
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 Thousands	Dec. 31, 2018	Dec. 31, 2017
Payables and Accruals [Abstract]
Trade accounts payable	$ 274,900	$ 339,600
Excise taxes/withholdings payable	89,700	89,400
Accrued insurance obligations	21,800	21,400
Accrued taxes other than income	26,600	25,300
Other	43,900	37,700
Accounts payable and accrued liabilities	$ 456,900	$ 513,400

Long-Term Debt (Summary of Long

Long-Term Debt (Summary of Long-Term Debt) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Apr. 25, 2017	Aug. 14, 2013
Debt Instrument [Line Items]
Capitalized lease obligations, vehicles, due through 2022	$ 2,300	$ 2,400
Unamortized debt issuance costs	(3,800)	(5,100)
Total long-term debt	863,300	880,800
Less current maturities	21,200	19,900
Long-term debt	842,100	860,900
Senior Notes | 6.00% senior notes due 2023 (net of unamortized discount of $4.1 at 2018 and $5.0 at 2017)
Debt Instrument [Line Items]
Long-term debt	495,900	495,000
Unamortized discount	$ 4,100	5,000
Interest rate (percent)	6.00%			6.00%
Senior Notes | 5.625% senior notes due 2027 (net of unamortized discount of $3.1 at 2018 and $3.5 at 2017)
Debt Instrument [Line Items]
Long-term debt	$ 296,900	296,500
Unamortized discount	$ 3,100	3,500
Interest rate (percent)	5.625%		5.625%
Secured Debt | Term loan due 2020 (effective rate of 5.0% at 2018 and 4.15% at 2017 ) | Term Loan
Debt Instrument [Line Items]
Long-term debt	$ 72,000	$ 92,000
Effective interest rate	5.00%	4.15%

Long-Term Debt (Narrative) (Det

Long-Term Debt (Narrative) (Details)	Mar. 10, 2016USD ($)	Dec. 31, 2018USD ($)	Apr. 25, 2017USD ($)	Aug. 30, 2013USD ($)	Aug. 14, 2013USD ($)
Debt Instrument [Line Items]
Fixed charge coverage ratio		1.10
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		0.15676
Dividend restrictions description		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, 2018, 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, 2018, the Company had a surplus of approximately $43.7 million of our net income and retained earnings subject to such restrictions before the fixed charge coverage ratio would fall below 1.0 to 1.0.
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%
Interest period one (in months)		1 month
Interest period two (in months)		2 months
Interest period three (in months)		3 months
Interest period four (in months)		6 months
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				$ 450,000,000
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			150,000,000
Principal payment period	10,000,000	$ 5,000,000
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%
Incremental Facility
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 150,000,000			$ 200,000,000
Letter Of Credit
Debt Instrument [Line Items]
Line of credit facility, sublimit		$ 200,000,000
Senior Notes | 6.00% senior notes due 2023
Debt Instrument [Line Items]
Interest rate (percent)		6.00%			6.00%
Senior notes					$ 500,000,000
Senior Notes | 5.625% senior notes due 2027
Debt Instrument [Line Items]
Interest rate (percent)		5.625%	5.625%
Senior notes			$ 300,000,000

Asset Retirement Obligations _3

Asset Retirement Obligations (ARO) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Asset Retirement Obligation Roll Forward
Balance at beginning of period	$ 28.2	$ 26.2
Accretion expense	2	1.8	$ 1.6
Settlements of liabilities	(0.3)	(0.3)
Liabilities incurred	0.8	0.5
Balance at end of period	$ 30.7	$ 28.2	$ 26.2

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	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income (loss) from continuing operations before income taxes	$ 100.5	$ 57	$ 69.1	$ 47.3	$ 51.2	$ 108.8	$ 89.9	$ (9.8)	$ 273.9	$ 240.1	$ 352.1
Federal - Current									18.4	39.2	74.9
Federal - Deferred									31	(50.7)	38.8
State - Current and deferred									10.9	6.3	16.9
Total									$ 60.3	$ (5.2)	$ 130.6

Income Taxes (Schedule Of Recon

Income Taxes (Schedule Of Reconciliation Of Income Taxes To Statutory Rate) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income tax expense based on the U.S. statutory tax rate		$ 57.5	$ 84	$ 123.2
State income taxes, net of federal benefit		8.3	3	11.5
Effect of U.S. tax law change	$ (88.9)	0	(88.9)	0
Other, net		(5.5)	(3.3)	(4.1)
Total		$ 60.3	$ (5.2)	$ 130.6

Income Taxes (Summary Of Deferr

Income Taxes (Summary Of Deferred Tax Assets And Deferred Tax Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets
Property costs and asset retirement obligations	$ 3.3	$ 2.8
Employee benefits	6.3	4.4
Other deferred tax assets	2.6	3.5
Total gross deferred tax assets	12.2	10.7
Deferred tax liabilities
Accumulated depreciation and amortization	(171.6)	(142.1)
State deferred taxes	(25.9)	(18.9)
Other deferred tax liabilities	(6.9)	(3.9)
Total gross deferred tax liabilities	(204.4)	(164.9)
Net deferred tax liabilities	$ (192.2)	$ (154.2)

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Contingency [Line Items]
Tax benefit related to Tax Cuts and Jobs Act	$ 88.9	$ 0	$ 88.9	$ 0
Income tax expense, net benefits for interest and penalties		(1.6)	0.4	$ 1.5
Accounting Standards Update 2016-09
Income Tax Contingency [Line Items]
Excess tax benefits		$ 2.5	$ 2.2

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, 2018	Dec. 31, 2017
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at January 1	$ 4.4	$ 7.9
Additions for tax positions related to prior years	0	4.4
Additions for tax positions related to current year	0.2	0
Settlements with taxing authorities	(3.9)	(5.5)
Expiration of statutes of limitation	0	(2.4)
Balance at December 31	$ 0.7	$ 4.4

Incentive Plans (Narrative) (De

Incentive Plans (Narrative) (Details)	12 Months Ended				64 Months Ended
	Dec. 31, 2018USD ($)plan$ / sharescompanyshares	Dec. 31, 2017USD ($)shares	Dec. 31, 2016USD ($)shares	Dec. 31, 2013$ / shares	Dec. 31, 2018USD ($)plancompanyshares	Feb. 12, 2014shares	Aug. 30, 2013shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of share based compensation plans | plan	2				2
Shares granted (in shares)	97,600	114,800	96,500
Unrecognized compensation cost related to stock option awards | $	$ 12,200,000				$ 12,200,000
Unrecognized compensation cost related to stock option awards, weighted average period for recognition (in years)	1 year 266 days
Total income tax benefits realized from tax deductions related to stock option exercises under share-based payment arrangements | $	$ 2,100,000	$ 600,000	$ 1,600,000
Murphy Oil
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum grant date fair value of options replaced (in dollars per share) | $ / shares				$ 32.53
Maximum grant date fair value of options replaced (in dollars per share) | $ / shares				$ 40.25
2013 Long-Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares authorized for incentive plan (in shares)						5,500,000	10,000,000
Maximum number of shares per employee (in shares)	1,000,000
Maximum amount payable | $	$ 5,000,000
Shares granted (in shares)					2,053,499
Shares available for grant (in shares)	3,446,501				3,446,501
2013 Long-Term Incentive Plan [Member] | Murphy Oil
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)	2 years
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				500,000
Shares available for grant (in shares)	389,457				389,457
Restricted stock units issued (in shares)					110,543
2013 Stock Plan For Non-Employee Directors | Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)	3 years
Restricted stock units issued (in shares)	10,921	15,948	19,900
Restricted stock units issued, weighted average grant date fair value (in dollars per share) | $ / shares	$ 69.42
MUSA 2013 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units issued (in shares)	69,179	111,471	74,325
Option term (in years)	7 years
MUSA 2013 Plan | Restricted Stock 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	$ 71.91
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	$ 71
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 | company	16				16
Restricted stock units issued, weighted average grant date fair value (in dollars per share) | $ / shares	$ 87.60

Incentive Plans (Schedule of Sh

Incentive Plans (Schedule of Share-Based Plan Amounts Recognized) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Compensation charged against income before income tax benefit	$ 9.2	$ 7.5	$ 9.3
Related income tax benefit recognized in income	$ 1.9	$ 2.6	$ 3.3

Incentive Plans (Summary of Val

Incentive Plans (Summary of Valuation Assumptions) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2012	Dec. 31, 2011
Murphy Oil Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility, minimum				37.00%	37.00%
Expected volatility, maximum				39.62%	39.62%
Risk-free interest rate, minimum				0.55%	0.55%
Risk-free interest rate, maximum				2.10%	2.10%
MUSA 2013 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value per option grant (in dollars per share)	$ 17.32	$ 15.45	$ 16.08
Dividend yield	0.00%	0.00%	0.00%
Expected volatility	27.00%	26.00%	26.10%
Risk-free interest rate	2.43%	1.65%	1.26%
Expected life (in years)	3 years 11 months	4 years 2 months	5 years 8 months
Minimum | Murphy Oil Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value per option grant (in dollars per share)				$ 12.37	$ 12.37
Dividend yield				1.80%	1.80%
Expected life (in years)				4 years	4 years
Maximum | Murphy Oil Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value per option grant (in dollars per share)				$ 20.34	$ 20.34
Dividend yield				2.27%	2.27%
Expected life (in years)				5 years 2 months 12 days	5 years 2 months 12 days

Incentive Plans (Summary of Cha

Incentive Plans (Summary of Changes in Stock Options Outstanding) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Number of Shares (in shares)
Beginning balance (in shares)	465,900	420,937	465,756
Granted at FMV (in shares)	97,600	114,800	96,500
Exercised (in shares)	(220,938)	(43,887)	(126,969)
Forfeited (in shares)	(32,200)	(25,950)	(14,350)
Ending balance (in shares)	310,362	465,900	420,937
Average Exercise Price (in dollars per share)
Beginning balance (in dollars per share)	$ 52.39	$ 47.88	$ 42.22
Granted at FMV (in dollars per share)	71.07	65.75	59.11
Exercised (in dollars per share)	39.48	37.41	34.48
Forfeited (in dollars per share)	69.21	63.63	58.28
Ending balance (in dollars per share)	$ 65.71	$ 52.39	$ 47.88
Exercisable (in shares)	100,662	254,375	218,937
Shares exercisable, average exercise price (in dollars per share)	$ 64.17	$ 42.80	$ 38.32

Incentive Plans (Summary of Add

Incentive Plans (Summary of Additional Stock Option Information) (Details)	12 Months Ended
	Dec. 31, 2018USD ($)$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding (in shares) | shares	310,362
Options outstanding, average remaining life (in years)	4 years 8 months 5 days
Options outstanding, aggregate intrinsic value | $	$ 3,391,739
Options exercisable (in shares) | shares	100,662
Options exercisable, average remaining life (in years)	3 years 4 months 28 days
Options exercisable, aggregate intrinsic value | $	$ 1,255,454
$32.53 to $39.99
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Lower range limit of exercise price (in dollars per share) | $ / shares	$ 32.53
Upper range limit of exercise price (in dollars per share) | $ / shares	$ 39.99
Options outstanding (in shares) | shares	7,062
Options outstanding, average remaining life (in years)	3 years 2 months 19 days
Options outstanding, aggregate intrinsic value | $	$ 280,472
Options exercisable (in shares) | shares	7,062
Options exercisable, average remaining life (in years)	3 years 2 months 19 days
Options exercisable, aggregate intrinsic value | $	$ 280,472
$40.00 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	$ 40
Upper range limit of exercise price (in dollars per share) | $ / shares	$ 59.99
Options outstanding (in shares) | shares	74,800
Options outstanding, average remaining life (in years)	4 years 1 month 13 days
Options outstanding, aggregate intrinsic value | $	$ 1,311,244
Options exercisable (in shares) | shares	35,500
Options exercisable, average remaining life (in years)	4 years 1 month 13 days
Options exercisable, aggregate intrinsic value | $	$ 622,315
$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) | shares	94,000
Options outstanding, average remaining life (in years)	5 years 1 month 9 days
Options outstanding, aggregate intrinsic value | $	$ 1,023,660
Options exercisable (in shares) | shares	0
Options exercisable, average remaining life (in years)	0 years
Options exercisable, aggregate intrinsic value | $	$ 0
$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) | shares	134,500
Options outstanding, average remaining life (in years)	4 years 9 months 11 days
Options outstanding, aggregate intrinsic value | $	$ 776,363
Options exercisable (in shares) | shares	58,100
Options exercisable, average remaining life (in years)	3 years 4 days
Options exercisable, aggregate intrinsic value | $	$ 352,667

Incentive Plans (Summary of Res

Incentive Plans (Summary of Restricted Stock Unit Activity) (Details) - shares	12 Months Ended			64 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018
MUSA 2013 Plan
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning balance (in shares)	259,016	269,345	356,300
Granted at FMV (in shares)	69,179	111,471	74,325
Vested and issued (in shares)	(96,815)	(60,688)	(142,392)
Forfeited (in shares)	(37,902)	(61,112)	(18,888)
Ending balance (in shares)	193,478	259,016	269,345	193,478
MUSA 2013 Plan | Performance Units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning balance (in shares)	124,724	147,740	102,394
Granted at FMV (in shares)	66,284	53,800	53,300
Vested and issued (in shares)	(51,296)	(60,816)	0
Forfeited (in shares)	(15,300)	(16,000)	(7,954)
Ending balance (in shares)	124,412	124,724	147,740	124,412
2013 Stock Plan For Non-Employee Directors
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Granted at FMV (in shares)				110,543
2013 Stock Plan For Non-Employee Directors | Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning balance (in shares)	45,346	49,342	63,774
Granted at FMV (in shares)	10,921	15,948	19,900
Vested and issued (in shares)	(15,250)	(19,944)	(34,332)
Forfeited (in shares)	0	0	0
Ending balance (in shares)	41,017	45,346	49,342	41,017

Employee and Retiree Benefit _2

Employee and Retiree Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Profit Sharing Plan
Defined Contribution Plan Disclosure [Line Items]
Profit sharing contributions	$ (0.8)	$ 2.2	$ 1.8
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	$ 9.7	$ 12.1	$ 10.5

Financial Instruments and Ris_2

Financial Instruments and Risk Management (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Cash deposits related to commodity derivative contracts	$ 1	$ 2.7

Earnings Per Share (Narrative)

Earnings Per Share (Narrative) (Details)	Aug. 30, 2013shares	May 31, 2014USD ($)$ / shares	Dec. 31, 2017USD ($)$ / sharesshares	Dec. 31, 2014shares	Dec. 31, 2018USD ($)$ / sharesshares	Dec. 31, 2017USD ($)$ / sharesshares	Dec. 31, 2016USD ($)	Dec. 31, 2015$ / sharesshares	Jan. 25, 2016capital_program	Oct. 31, 2014USD ($)
Equity, Class of Treasury Stock [Line Items]
Issuance of stock at the separation and distribution (in shares) | shares	46,743,316
Common stock acquired					$ 144,400,000	$ 206,000,000	$ 323,300,000
May 2014 Share Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, approved amount		$ 50,000,000
Stock repurchase program, shares acquired (in shares) | shares				1,040,636
Stock repurchase program, average price per share (in dollars per share) | $ / shares		$ 48.07
Two Hundred Fifty Million Dollar Share Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, approved amount										$ 250,000,000
Stock repurchase program, shares acquired (in shares) | shares								4,196,349
Stock repurchase program, average price per share (in dollars per share) | $ / shares								$ 59.58
January 2016 Share Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, shares acquired (in shares) | shares			379,054		1,994,632	2,586,190
Common stock acquired					$ 144,400,000
Stock repurchase program, average price per share (in dollars per share) | $ / shares			$ 77.20		$ 72.39	$ 68.34
Stock repurchase program, authorized amount			$ 500,000,000			$ 500,000,000
Stock repurchase program, number of capital programs | capital_program									2
Stock repurchase program, shares acquired			$ 29,000,000

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	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings per common share:
Net income	$ 77.5	$ 45	$ 51.8	$ 39.3	$ 124.9	$ 67.9	$ 55.5	$ (3)	$ 213.6	$ 245.3	$ 221.5
Weighted average common shares outstanding (in thousands) (in shares)									32,674	35,816	39,269
Earnings per common share (in dollars per share)	$ 2.40	$ 1.40	$ 1.59	$ 1.17	$ 3.62	$ 1.92	$ 1.52	$ (0.08)	$ 6.54	$ 6.85	$ 5.64
Earnings per common share - assuming dilution:
Net income	$ 77.5	$ 45	$ 51.8	$ 39.3	$ 124.9	$ 67.9	$ 55.5	$ (3)	$ 213.6	$ 245.3	$ 221.5
Weighted average common shares outstanding (in thousands) (in shares)									32,674	35,816	39,269
Common equivalent shares:
Share-based awards (in shares)									309	340	377
Weighted average common shares outstanding - assuming dilution (in thousands) (in shares)									32,983	36,156	39,646
Earnings per common share assuming dilution (in dollars per share)	$ 2.38	$ 1.38	$ 1.58	$ 1.16	$ 3.58	$ 1.90	$ 1.51	$ (0.08)	$ 6.48	$ 6.78	$ 5.59

Other Financial Information (Na

Other Financial Information (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Income taxes paid (collected), net	$ 17.4	$ 51.7	$ 70.8
Interest paid, net of amounts capitalized	$ 50.4	$ 41.5	$ 37.1

Other Financial Information (Su

Other Financial Information (Summary Of Changes In Operating Working Capital) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accounts receivable	$ 86.6	$ (41.7)	$ (47.2)
Inventories	(39)	(16.3)	2.1
Prepaid expenses and other current assets	11.4	(5.2)	13.7
Accounts payable and accrued liabilities	(56.7)	26.9	83.4
Income taxes payable	0	(0.6)	1.7
Net decrease (increase) in noncash operating working capital	$ 2.3	$ (36.9)	$ 53.7

Assets and Liabilities Measur_3

Assets and Liabilities Measure at Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current and long-term debt	$ (863.3)	$ (880.8)
Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current and long-term debt	$ (866.7)	$ (904.9)

Commitments (Details)

Commitments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Expected future rental payments under operating leases in 2019	$ 13.7
Expected future rental payments under operating leases in 2020	13.3
Expected future rental payments under operating leases in 2021	12.5
Expected future rental payments under operating leases in 2022	11.7
Expected future rental payments under operating leases in 2023	11.1
Rental expense for noncancelable operating leases	$ 15.2	$ 14	$ 23.2
Take-Or-Pay Contracts
Other Commitments [Line Items]
Term of take-or-pay contract	2 years 8 months
Take-or-pay contract due in 2019	$ 7.9
Take-or-pay contract due in 2020	7.9
Take-or-pay contract due in 2021	4.9
Capital Addition Purchase Commitments
Other Commitments [Line Items]
Commitments for capital expenditures	240.5
Construction in Progress
Other Commitments [Line Items]
Commitments for capital expenditures	219.5
Building Improvements
Other Commitments [Line Items]
Commitments for capital expenditures	$ 15.4

Contingencies (Details)

Contingencies (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)site
Commitments and Contingencies Disclosure [Abstract]
Number of Superfund sites for which company may be liable | site	1
Liability accrued	$ 0.1
Workers' compensation deductible (per occurrence)	1
General liability insurance deductible	3
Auto liability insurance deductible	0.3
Workers' compensation accrued liability	19.8
Outstanding letters of credit	$ 16.1

Recent Accounting and Reporti_2

Recent Accounting and Reporting Rules Narrative (Details) - Subsequent Event - Accounting Standards Update 2016-02 $ in Millions	Jan. 01, 2019USD ($)
Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use asset	$ 100
Lease liability	0
Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use asset	115
Lease liability	$ 115

Business Segments (Summary of I

Business Segments (Summary of Information by Business Segment) (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018USD ($)	Sep. 30, 2018USD ($)	Jun. 30, 2018USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2018USD ($)segment	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Segment Reporting [Abstract]
Number of operating segments | segment									1
Segment Reporting Information [Line Items]
Net income (loss)	$ 77,500	$ 45,000	$ 51,800	$ 39,300	$ 124,900	$ 67,900	$ 55,500	$ (3,000)	$ 213,600	$ 245,300	$ 221,500
Revenues from external customers									14,362,900	12,826,600	11,594,600
Interest income									1,500	1,300	600
Interest expense									(52,900)	(46,700)	(39,700)
Income tax expense (benefit)									60,300	(5,200)	130,600
Significant noncash charges (credits)
Depreciation and amortization									134,000	116,900	98,600
Accretion of asset retirement obligations									2,000	1,800	1,600
Deferred and noncurrent income taxes (benefits)									(37,900)	50,400	(40,400)
Additions to property, plant and equipment									193,800	273,700	263,900
Total assets at year-end	2,360,800				2,331,000				2,360,800	2,331,000	2,088,700
Operating Segment | Marketing
Segment Reporting Information [Line Items]
Net income (loss)									214,200	295,300	249,800
Revenues from external customers									14,362,300	12,826,200	11,594,300
Interest income									0	0	0
Interest expense									(100)	(100)	(100)
Income tax expense (benefit)									69,500	(2,900)	147,200
Significant noncash charges (credits)
Depreciation and amortization									124,500	110,500	92,200
Accretion of asset retirement obligations									2,000	1,800	1,600
Deferred and noncurrent income taxes (benefits)									(39,000)	61,300	(51,300)
Additions to property, plant and equipment									169,200	234,000	239,100
Total assets at year-end	2,012,000				2,023,400				2,012,000	2,023,400	1,858,000
Corporate and Other Assets
Segment Reporting Information [Line Items]
Net income (loss)									(600)	(50,000)	(28,300)
Revenues from external customers									600	400	300
Interest income									1,500	1,300	600
Interest expense									(52,800)	(46,600)	(39,600)
Income tax expense (benefit)									(9,200)	(2,300)	(16,600)
Significant noncash charges (credits)
Depreciation and amortization									9,500	6,400	6,400
Accretion of asset retirement obligations									0	0	0
Deferred and noncurrent income taxes (benefits)									1,100	(10,900)	10,900
Additions to property, plant and equipment									24,600	39,700	24,800
Total assets at year-end	$ 348,800				$ 307,600				$ 348,800	$ 307,600	$ 230,700

Guarantor Subsidiaries (Narrati

Guarantor Subsidiaries (Narrative) (Details) - Senior Notes	Dec. 31, 2018	Apr. 25, 2017	Aug. 14, 2013
6.00% senior notes due 2023
Debt Instrument [Line Items]
Interest rate (percent)	6.00%		6.00%
5.625% senior notes due 2027
Debt Instrument [Line Items]
Interest rate (percent)	5.625%	5.625%

Guarantor Subsidiaries (Consoli

Guarantor Subsidiaries (Consolidating Balance Sheet) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current assets
Cash and cash equivalents	$ 184,500	$ 170,000	$ 153,800	$ 33,700
Accounts receivable—trade, less allowance for doubtful accounts	138,800	225,200
Inventories, at lower of cost or market	221,500	182,500
Prepaid expenses and other current assets	25,300	36,500
Total current assets	570,100	614,200
Property, plant and equipment, at cost less accumulated depreciation and amortization	1,748,200	1,679,500
Investments in subsidiaries	0	0
Other assets	42,500	37,300
Total assets	2,360,800	2,331,000	2,088,700
Current liabilities
Current maturities of long-term debt	21,200	19,900
Inter-company accounts payable	0	0
Trade accounts payable and accrued liabilities	456,900	513,400
Total current liabilities	478,100	533,300
Long-term debt, including capitalized lease obligations	842,100	860,900
Deferred income taxes	192,200	154,200
Asset retirement obligations	30,700	28,200
Deferred credits and other liabilities	10,400	16,000
Total liabilities	1,553,500	1,592,600
Stockholders' Equity
Preferred Stock, par $0.01	0	0
Common Stock, par $0.01	500	500
Treasury stock	(940,300)	(806,500)
Additional paid in capital (APIC)	539,000	549,900
Retained earnings	1,208,100	994,500
Total stockholders' equity	807,300	738,400	697,000	792,200
Total liabilities and stockholders' equity	2,360,800	2,331,000
Eliminations
Current assets
Cash and cash equivalents	0	0	0	0
Accounts receivable—trade, less allowance for doubtful accounts	0	0
Inventories, at lower of cost or market	0	0
Prepaid expenses and other current assets	0	0
Total current assets	0	0
Property, plant and equipment, at cost less accumulated depreciation and amortization	0	0
Investments in subsidiaries	(2,581,400)	(2,368,300)
Other assets	0	0
Total assets	(2,581,400)	(2,368,300)
Current liabilities
Current maturities of long-term debt	0	0
Inter-company accounts payable	0	0
Trade accounts payable and accrued liabilities	0	0
Total current liabilities	0	0
Long-term debt, including capitalized lease obligations	0	0
Deferred income taxes	0	0
Asset retirement obligations	0	0
Deferred credits and other liabilities	0	0
Total liabilities	0	0
Stockholders' Equity
Preferred Stock, par $0.01	0	0
Common Stock, par $0.01	(100)	(100)
Treasury stock	0	0
Additional paid in capital (APIC)	(1,368,400)	(1,368,400)
Retained earnings	(1,212,900)	(999,800)
Total stockholders' equity	(2,581,400)	(2,368,300)
Total liabilities and stockholders' equity	(2,581,400)	(2,368,300)
Parent Company | Reportable Legal Entities
Current assets
Cash and cash equivalents	0	0	0	0
Accounts receivable—trade, less allowance for doubtful accounts	0	0
Inventories, at lower of cost or market	0	0
Prepaid expenses and other current assets	0	0
Total current assets	0	0
Property, plant and equipment, at cost less accumulated depreciation and amortization	0	0
Investments in subsidiaries	2,437,000	2,223,400
Other assets	0	0
Total assets	2,437,000	2,223,400
Current liabilities
Current maturities of long-term debt	0	0
Inter-company accounts payable	(100)	829,200
Trade accounts payable and accrued liabilities	0	0
Total current liabilities	(100)	829,200
Long-term debt, including capitalized lease obligations	0	0
Deferred income taxes	0	0
Asset retirement obligations	0	0
Deferred credits and other liabilities	0	0
Total liabilities	(100)	829,200
Stockholders' Equity
Preferred Stock, par $0.01	0	0
Common Stock, par $0.01	500	500
Treasury stock	(940,300)	(806,500)
Additional paid in capital (APIC)	1,195,100	1,205,700
Retained earnings	2,181,800	994,500
Total stockholders' equity	2,437,100	1,394,200
Total liabilities and stockholders' equity	2,437,000	2,223,400
Issuer | Reportable Legal Entities
Current assets
Cash and cash equivalents	184,000	169,900	153,800	33,700
Accounts receivable—trade, less allowance for doubtful accounts	138,800	225,200
Inventories, at lower of cost or market	221,500	182,500
Prepaid expenses and other current assets	25,100	36,500
Total current assets	569,400	614,100
Property, plant and equipment, at cost less accumulated depreciation and amortization	1,745,900	1,678,300
Investments in subsidiaries	144,400	144,900
Other assets	42,500	37,300
Total assets	2,502,200	2,474,600
Current liabilities
Current maturities of long-term debt	21,200	19,900
Inter-company accounts payable	203,000	(624,100)
Trade accounts payable and accrued liabilities	456,900	513,400
Total current liabilities	681,100	(90,800)
Long-term debt, including capitalized lease obligations	842,100	860,900
Deferred income taxes	192,200	154,200
Asset retirement obligations	30,700	28,200
Deferred credits and other liabilities	10,400	16,000
Total liabilities	1,756,500	968,500
Stockholders' Equity
Preferred Stock, par $0.01	0	0
Common Stock, par $0.01	0	0
Treasury stock	0	0
Additional paid in capital (APIC)	572,800	573,100
Retained earnings	172,900	933,000
Total stockholders' equity	745,700	1,506,100
Total liabilities and stockholders' equity	2,502,200	2,474,600
Guarantor Subsidiaries | Reportable Legal Entities
Current assets
Cash and cash equivalents	500	100	0	0
Accounts receivable—trade, less allowance for doubtful accounts	0	0
Inventories, at lower of cost or market	0	0
Prepaid expenses and other current assets	200	0
Total current assets	700	100
Property, plant and equipment, at cost less accumulated depreciation and amortization	2,300	1,200
Investments in subsidiaries	0	0
Other assets	0	0
Total assets	3,000	1,300
Current liabilities
Current maturities of long-term debt	0	0
Inter-company accounts payable	(48,600)	(50,800)
Trade accounts payable and accrued liabilities	0	0
Total current liabilities	(48,600)	(50,800)
Long-term debt, including capitalized lease obligations	0	0
Deferred income taxes	0	0
Asset retirement obligations	0	0
Deferred credits and other liabilities	0	0
Total liabilities	(48,600)	(50,800)
Stockholders' Equity
Preferred Stock, par $0.01	0	0
Common Stock, par $0.01	100	100
Treasury stock	0	0
Additional paid in capital (APIC)	52,000	52,000
Retained earnings	(500)	0
Total stockholders' equity	51,600	52,100
Total liabilities and stockholders' equity	3,000	1,300
Non-Guarantor Subsidiaries | Reportable Legal Entities
Current assets
Cash and cash equivalents	0	0	$ 0	$ 0
Accounts receivable—trade, less allowance for doubtful accounts	0	0
Inventories, at lower of cost or market	0	0
Prepaid expenses and other current assets	0	0
Total current assets	0	0
Property, plant and equipment, at cost less accumulated depreciation and amortization	0	0
Investments in subsidiaries	0	0
Other assets	0	0
Total assets	0	0
Current liabilities
Current maturities of long-term debt	0	0
Inter-company accounts payable	(154,300)	(154,300)
Trade accounts payable and accrued liabilities	0	0
Total current liabilities	(154,300)	(154,300)
Long-term debt, including capitalized lease obligations	0	0
Deferred income taxes	0	0
Asset retirement obligations	0	0
Deferred credits and other liabilities	0	0
Total liabilities	(154,300)	(154,300)
Stockholders' Equity
Preferred Stock, par $0.01	0	0
Common Stock, par $0.01	0	0
Treasury stock	0	0
Additional paid in capital (APIC)	87,500	87,500
Retained earnings	66,800	66,800
Total stockholders' equity	154,300	154,300
Total liabilities and stockholders' equity	$ 0	$ 0

Guarantor Subsidiaries (Conso_2

Guarantor Subsidiaries (Consolidating Balance Sheet Parenthetical) (Details) - USD ($) $ / shares in Units, $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Guarantor Subsidiaries [Abstract]
Accounts receivable - trade, allowance for doubtful accounts	$ 1.1	$ 1.1
Accumulated depreciation and amortization	$ 974.2	$ 874.7
Preferred stock par value (in dollars per share)	$ 0.01	$ 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)	14,505,681	12,675,630

Guarantor Subsidiaries (Conso_3

Guarantor Subsidiaries (Consolidating Income Statement) (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Revenues
Operating revenues		$ 3,501.7	$ 3,788	$ 3,829	$ 3,244.2	$ 3,379.5	$ 3,236.3	$ 3,211.2	$ 2,999.6	$ 14,362.9	$ 12,826.6	$ 11,594.6
Operating Expenses
Station and other operating expenses										541.3	514.9	493.3
Depreciation and amortization										134	116.9	98.6
Selling, general and administrative										136.2	141.2	122.7
Accretion of asset retirement obligations										2	1.8	1.6
Total operating expenses										14,087.1	12,539.4	11,294.7
Net settlement proceeds										50.4	0	0
Gain (loss) on sale of assets										(1.1)	(3.9)	88.2
Income from operations										325.1	283.3	388.1
Other income (expense)
Interest income										1.5	1.3	0.6
Interest expense										(52.9)	(46.7)	(39.7)
Other nonoperating income (expense)										0.2	2.2	3.1
Total other income (expense)										(51.2)	(43.2)	(36)
Income before income taxes		100.5	57	69.1	47.3	51.2	108.8	89.9	(9.8)	273.9	240.1	352.1
Income tax expense (benefit)										60.3	(5.2)	130.6
Income (loss)		77.5	45	51.8	39.3	124.9	67.9	55.5	(3)	213.6	245.3	221.5
Equity earnings in affiliates, net of tax										0	0	0
Net Income		$ 77.5	$ 45	$ 51.8	$ 39.3	$ 124.9	$ 67.9	$ 55.5	$ (3)	213.6	245.3	221.5
Eliminations
Operating Revenues
Operating revenues										0	0	0
Operating Expenses
Station and other operating expenses										0	0	0
Depreciation and amortization										0	0	0
Selling, general and administrative										0	0	0
Accretion of asset retirement obligations										0	0	0
Total operating expenses										0	0	0
Net settlement proceeds										0
Gain (loss) on sale of assets										0	0	0
Income from operations										0	0	0
Other income (expense)
Interest income										0	0	0
Interest expense										0	0	0
Other nonoperating income (expense)										0	0	0
Total other income (expense)										0	0	0
Income before income taxes										0	0	0
Income tax expense (benefit)										0	0	0
Income (loss)										0	0	0
Equity earnings in affiliates, net of tax										(213.1)	(245.3)	(221.5)
Net Income										(213.1)	(245.3)	(221.5)
Parent Company | Reportable Legal Entities
Operating Revenues
Operating revenues										0	0	0
Operating Expenses
Station and other operating expenses										0	0	0
Depreciation and amortization										0	0	0
Selling, general and administrative										0	0	0
Accretion of asset retirement obligations										0	0	0
Total operating expenses										0	0	0
Net settlement proceeds										0
Gain (loss) on sale of assets										0	0	0
Income from operations										0	0	0
Other income (expense)
Interest income										0	0	0
Interest expense										0	0	0
Other nonoperating income (expense)										973.7	0	0
Total other income (expense)										973.7	0	0
Income before income taxes										973.7	0	0
Income tax expense (benefit)										0	0	0
Income (loss)										973.7	0	0
Equity earnings in affiliates, net of tax										213.6	245.3	221.5
Net Income										1,187.3	245.3	221.5
Issuer | Reportable Legal Entities
Operating Revenues
Operating revenues										14,362.9	12,826.6	11,594.6
Operating Expenses
Station and other operating expenses										541.3	514.9	493.3
Depreciation and amortization										134	116.9	98.6
Selling, general and administrative										136.2	141.2	122.7
Accretion of asset retirement obligations										2	1.8	1.6
Total operating expenses										14,087.1	12,539.4	11,294.7
Net settlement proceeds										50.4
Gain (loss) on sale of assets										(1.1)	(3.9)	88.2
Income from operations										325.1	283.3	388.1
Other income (expense)
Interest income										1.5	1.3	0.6
Interest expense										(52.9)	(46.7)	(39.7)
Other nonoperating income (expense)										(972.9)	2.2	3.1
Total other income (expense)										(1,024.3)	(43.2)	(36)
Income before income taxes										(699.2)	240.1	352.1
Income tax expense (benefit)										60.4	(5.2)	130.6
Income (loss)										(759.6)	245.3	221.5
Equity earnings in affiliates, net of tax										(0.5)	0	0
Net Income										(760.1)	245.3	221.5
Guarantor Subsidiaries | Reportable Legal Entities
Operating Revenues
Operating revenues										0	0	0
Operating Expenses
Station and other operating expenses										0	0	0
Depreciation and amortization										0	0	0
Selling, general and administrative										0	0	0
Accretion of asset retirement obligations										0	0	0
Total operating expenses										0	0	0
Net settlement proceeds										0
Gain (loss) on sale of assets										0	0	0
Income from operations										0	0	0
Other income (expense)
Interest income										0	0	0
Interest expense										0	0	0
Other nonoperating income (expense)										(0.6)	0	0
Total other income (expense)										(0.6)	0	0
Income before income taxes										(0.6)	0	0
Income tax expense (benefit)										(0.1)	0	0
Income (loss)										(0.5)	0	0
Equity earnings in affiliates, net of tax										0	0	0
Net Income										(0.5)	0	0
Non-Guarantor Subsidiaries | Reportable Legal Entities
Operating Revenues
Operating revenues										0	0	0
Operating Expenses
Station and other operating expenses										0	0	0
Depreciation and amortization										0	0	0
Selling, general and administrative										0	0	0
Accretion of asset retirement obligations										0	0	0
Total operating expenses										0	0	0
Net settlement proceeds										0
Gain (loss) on sale of assets										0	0	0
Income from operations										0	0	0
Other income (expense)
Interest income										0	0	0
Interest expense										0	0	0
Other nonoperating income (expense)										0	0	0
Total other income (expense)										0	0	0
Income before income taxes										0	0	0
Income tax expense (benefit)										0	0	0
Income (loss)										0	0	0
Equity earnings in affiliates, net of tax										0	0	0
Net Income										0	0	0
Petroleum product sales
Operating Revenues
Operating revenues										11,858.4	10,287.9	9,070.6
Operating Expenses
Operating expenses	[1]									11,251.1	9,773.2	8,604
Petroleum product sales | Eliminations
Operating Revenues
Operating revenues										0	0	0
Operating Expenses
Operating expenses										0	0	0
Petroleum product sales | Parent Company | Reportable Legal Entities
Operating Revenues
Operating revenues										0	0	0
Operating Expenses
Operating expenses										0	0	0
Petroleum product sales | Issuer | Reportable Legal Entities
Operating Revenues
Operating revenues										11,858.4	10,287.9	9,070.6
Operating Expenses
Operating expenses										11,251.1	9,773.2	8,604
Petroleum product sales | Guarantor Subsidiaries | Reportable Legal Entities
Operating Revenues
Operating revenues										0	0	0
Operating Expenses
Operating expenses										0	0	0
Petroleum product sales | Non-Guarantor Subsidiaries | Reportable Legal Entities
Operating Revenues
Operating revenues										0	0	0
Operating Expenses
Operating expenses										0	0	0
Merchandise
Operating Revenues
Operating revenues										2,423	2,372.7	2,338.6
Operating Expenses
Operating expenses										2,022.5	1,991.4	1,974.5
Merchandise | Eliminations
Operating Revenues
Operating revenues										0	0	0
Operating Expenses
Operating expenses										0	0	0
Merchandise | Parent Company | Reportable Legal Entities
Operating Revenues
Operating revenues										0	0	0
Operating Expenses
Operating expenses										0	0	0
Merchandise | Issuer | Reportable Legal Entities
Operating Revenues
Operating revenues										2,423	2,372.7	2,338.6
Operating Expenses
Operating expenses										2,022.5	1,991.4	1,974.5
Merchandise | Guarantor Subsidiaries | Reportable Legal Entities
Operating Revenues
Operating revenues										0	0	0
Operating Expenses
Operating expenses										0	0	0
Merchandise | Non-Guarantor Subsidiaries | Reportable Legal Entities
Operating Revenues
Operating revenues										0	0	0
Operating Expenses
Operating expenses										0	0	0
Other operating revenues
Operating Revenues
Operating revenues										81.5	166	185.4
Other operating revenues | Eliminations
Operating Revenues
Operating revenues										0	0	0
Other operating revenues | Parent Company | Reportable Legal Entities
Operating Revenues
Operating revenues										0	0	0
Other operating revenues | Issuer | Reportable Legal Entities
Operating Revenues
Operating revenues										81.5	166	185.4
Other operating revenues | Guarantor Subsidiaries | Reportable Legal Entities
Operating Revenues
Operating revenues										0	0	0
Other operating revenues | Non-Guarantor Subsidiaries | Reportable Legal Entities
Operating Revenues
Operating revenues										$ 0	$ 0	$ 0
[1]	Years Ended December 31,(Millions of dollars except per share amounts)2018 2017 2016 Supplemental information: (a) Includes excise taxes of:$1,838.9 $1,973.1 $1,961.5

Guarantor Subsidiaries (Conso_4

Guarantor Subsidiaries (Consolidating Statement Of Cash Flow) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Financial Statements, Captions [Line Items]
Restricted cash												$ 0	$ 0	$ 0	$ 68.6
Operating Activities
Net income (loss)	$ 77.5	$ 45	$ 51.8	$ 39.3	$ 124.9	$ 67.9	$ 55.5	$ (3)	$ 213.6	$ 245.3	$ 221.5
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization									134	116.9	98.6
Deferred and noncurrent income tax charges (benefits)									37.9	(50.4)	40.4
Accretion of asset retirement obligations									2	1.8	1.6
Pretax (gains) losses from sale of assets									1.1	3.9	(88.2)
Net decrease (increase) in noncash operating working capital									2.3	(36.9)	53.7
Equity in earnings									0	0	0
Other operating activities - net									7.8	3	9.8
Net cash provided by operating activities									398.7	283.6	337.4
Investing Activities
Property additions									(204.3)	(258.3)	(262.1)
Proceeds from sale of assets									1.2	0.9	85.3
Changes in restricted cash									0	0	68.6
Other investing activities - net									(6)	(4.7)	(29)
Other									0	0	2.4
Net cash required by investing activities									(209.1)	(262.1)	(134.8)
Financing Activities
Purchase of treasury stock									(144.4)	(206)	(323.3)
Repayments of long-term debt									(21.3)	(131.4)	(20.4)
Additions to long-term debt									0	338.8	200
Debt issuance costs									0	(1.1)	(3.2)
Amounts related to share-based compensation									(9.4)	(5.6)	(4.2)
Net distributions to parent									0	0	0
Net cash required by financing activities									(175.1)	(5.3)	(151.1)
Net change in cash and cash equivalents									14.5	16.2	51.5
Cash, cash equivalents, and restricted cash at January 1				170				153.8	170	153.8	102.3
Cash, cash equivalents, and restricted cash at December 31	184.5				170				184.5	170	153.8
Reconciliation of Cash, Cash Equivalents and Restricted Cash
Cash, cash equivalents, and restricted cash	184.5			170	170			153.8	170	153.8	102.3	184.5	170	153.8	102.3
Eliminations
Condensed Financial Statements, Captions [Line Items]
Restricted cash														0	0
Operating Activities
Net income (loss)									(213.1)	(245.3)	(221.5)
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization									0	0	0
Deferred and noncurrent income tax charges (benefits)									0	0	0
Accretion of asset retirement obligations									0	0	0
Pretax (gains) losses from sale of assets									0	0	0
Net decrease (increase) in noncash operating working capital									0	0	0
Equity in earnings									213.1	245.3	221.5
Other operating activities - net									0	0	0
Net cash provided by operating activities									0	0	0
Investing Activities
Property additions									0	0	0
Proceeds from sale of assets									0	0	0
Changes in restricted cash											0
Other investing activities - net									0	0	0
Other											0
Net cash required by investing activities									0	0	0
Financing Activities
Purchase of treasury stock									0	0	0
Repayments of long-term debt									0	0	0
Additions to long-term debt										0	0
Debt issuance costs										0	0
Amounts related to share-based compensation									0	0	0
Net distributions to parent									0	0	0
Net cash required by financing activities									0	0	0
Net change in cash and cash equivalents									0	0	0
Cash, cash equivalents, and restricted cash at January 1				0				0	0	0	0
Cash, cash equivalents, and restricted cash at December 31	0				0				0	0	0
Reconciliation of Cash, Cash Equivalents and Restricted Cash
Cash, cash equivalents, and restricted cash	0			0	0			0	0	0	0	0	0	0	0
Parent Company | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Restricted cash														0	0
Operating Activities
Net income (loss)									1,187.3	245.3	221.5
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization									0	0	0
Deferred and noncurrent income tax charges (benefits)									0	0	0
Accretion of asset retirement obligations									0	0	0
Pretax (gains) losses from sale of assets									0	0	0
Net decrease (increase) in noncash operating working capital									0	0	0
Equity in earnings									(213.6)	(245.3)	(221.5)
Other operating activities - net									0	0	0
Net cash provided by operating activities									973.7	0	0
Investing Activities
Property additions									0	0	0
Proceeds from sale of assets									0	0	0
Changes in restricted cash											0
Other investing activities - net									0	0	0
Other											0
Net cash required by investing activities									0	0	0
Financing Activities
Purchase of treasury stock									(144.4)	(206)	(323.3)
Repayments of long-term debt									0	0	0
Additions to long-term debt										0	0
Debt issuance costs										0	0
Amounts related to share-based compensation									0	0	0
Net distributions to parent									(829.3)	206	323.3
Net cash required by financing activities									(973.7)	0	0
Net change in cash and cash equivalents									0	0	0
Cash, cash equivalents, and restricted cash at January 1				0				0	0	0	0
Cash, cash equivalents, and restricted cash at December 31	0				0				0	0	0
Reconciliation of Cash, Cash Equivalents and Restricted Cash
Cash, cash equivalents, and restricted cash	0			0	0			0	0	0	0	0	0	0	0
Issuer | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Restricted cash														0	68.6
Operating Activities
Net income (loss)									(760.1)	245.3	221.5
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization									134	116.9	98.6
Deferred and noncurrent income tax charges (benefits)									37.9	(50.4)	40.4
Accretion of asset retirement obligations									2	1.8	1.6
Pretax (gains) losses from sale of assets									1.1	3.9	(88.2)
Net decrease (increase) in noncash operating working capital									2.4	(36.9)	53.7
Equity in earnings									0.5	0	0
Other operating activities - net									7.8	3	9.8
Net cash provided by operating activities									(574.4)	283.6	337.4
Investing Activities
Property additions									(203.1)	(257.1)	(262.1)
Proceeds from sale of assets									1.2	0.9	85.3
Changes in restricted cash											68.6
Other investing activities - net									(6)	(4.7)	(29)
Other											2.4
Net cash required by investing activities									(207.9)	(260.9)	(134.8)
Financing Activities
Purchase of treasury stock									0	0	0
Repayments of long-term debt									(21.3)	(131.4)	(20.4)
Additions to long-term debt										338.8	200
Debt issuance costs										(1.1)	(3.2)
Amounts related to share-based compensation									(9.4)	(5.6)	(4.2)
Net distributions to parent									827.1	(207.3)	(323.3)
Net cash required by financing activities									796.4	(6.6)	(151.1)
Net change in cash and cash equivalents									14.1	16.1	51.5
Cash, cash equivalents, and restricted cash at January 1				169.9				153.8	169.9	153.8	102.3
Cash, cash equivalents, and restricted cash at December 31	184				169.9				184	169.9	153.8
Reconciliation of Cash, Cash Equivalents and Restricted Cash
Cash, cash equivalents, and restricted cash	184			169.9	169.9			153.8	169.9	153.8	102.3	184	169.9	153.8	102.3
Guarantor Subsidiaries | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Restricted cash														0	0
Operating Activities
Net income (loss)									(0.5)	0	0
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization									0	0	0
Deferred and noncurrent income tax charges (benefits)									0	0	0
Accretion of asset retirement obligations									0	0	0
Pretax (gains) losses from sale of assets									0	0	0
Net decrease (increase) in noncash operating working capital									(0.1)	0	0
Equity in earnings									0	0	0
Other operating activities - net									0	0	0
Net cash provided by operating activities									(0.6)	0	0
Investing Activities
Property additions									(1.2)	(1.2)	0
Proceeds from sale of assets									0	0	0
Changes in restricted cash											0
Other investing activities - net									0	0	0
Other											0
Net cash required by investing activities									(1.2)	(1.2)	0
Financing Activities
Purchase of treasury stock									0	0	0
Repayments of long-term debt									0	0	0
Additions to long-term debt										0	0
Debt issuance costs										0	0
Amounts related to share-based compensation									0	0	0
Net distributions to parent									2.2	1.3	0
Net cash required by financing activities									2.2	1.3	0
Net change in cash and cash equivalents									0.4	0.1	0
Cash, cash equivalents, and restricted cash at January 1				0.1				0	0.1	0	0
Cash, cash equivalents, and restricted cash at December 31	0.5				0.1				0.5	0.1	0
Reconciliation of Cash, Cash Equivalents and Restricted Cash
Cash, cash equivalents, and restricted cash	0.5			0.1	0.1			0	0.1	0	0	0.5	0.1	0	0
Non-Guarantor Subsidiaries | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Restricted cash														0	0
Operating Activities
Net income (loss)									0	0	0
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization									0	0	0
Deferred and noncurrent income tax charges (benefits)									0	0	0
Accretion of asset retirement obligations									0	0	0
Pretax (gains) losses from sale of assets									0	0	0
Net decrease (increase) in noncash operating working capital									0	0	0
Equity in earnings									0	0	0
Other operating activities - net									0	0	0
Net cash provided by operating activities									0	0	0
Investing Activities
Property additions									0	0	0
Proceeds from sale of assets									0	0	0
Changes in restricted cash											0
Other investing activities - net									0	0	0
Other											0
Net cash required by investing activities									0	0	0
Financing Activities
Purchase of treasury stock									0	0	0
Repayments of long-term debt									0	0	0
Additions to long-term debt										0	0
Debt issuance costs										0	0
Amounts related to share-based compensation									0	0	0
Net distributions to parent									0	0	0
Net cash required by financing activities									0	0	0
Net change in cash and cash equivalents									0	0	0
Cash, cash equivalents, and restricted cash at January 1				0				0	0	0	0
Cash, cash equivalents, and restricted cash at December 31	0				0				0	0	0
Reconciliation of Cash, Cash Equivalents and Restricted Cash
Cash, cash equivalents, and restricted cash	$ 0			$ 0	$ 0			$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0

Guarantor Subsidiaries (Conso_5

Guarantor Subsidiaries (Consolidating Statement Of Changes In Equity) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				$ 738,400				$ 697,000	$ 738,400	$ 697,000	$ 792,200
Issuance of common stock									0	(100)	0
Repurchase of common stock									(144,400)	(206,000)	(323,300)
Issuance of common stock									0	0	0
Amounts related to share-based compensation									(9,400)	(5,600)	(2,700)
Share-based compensation expense									9,100	7,600	9,300
Net income	$ 77,500	$ 45,000	$ 51,800	39,300	$ 124,900	$ 67,900	$ 55,500	(3,000)	213,600	245,300	221,500
Balance	807,300				738,400				807,300	738,400	697,000
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				500				500	500	500	500
Issuance of common stock									0	0	0
Balance	500				500				500	500	500
Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				(806,500)				(608,000)	(806,500)	(608,000)	(294,100)
Issuance of common stock									(10,600)	(7,500)	(9,400)
Repurchase of common stock									(144,400)	(206,000)	(323,300)
Balance	(940,300)				(806,500)				(940,300)	(806,500)	(608,000)
APIC
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				549,900				555,300	549,900	555,300	558,100
Issuance of common stock									10,600	7,400	9,400
Amounts related to share-based compensation									(9,400)	(5,600)	(2,700)
Reclassification of equity										0
Share-based compensation expense									9,100	7,600	9,300
Balance	539,000				549,900				539,000	549,900	555,300
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				994,500				749,200	994,500	749,200	527,700
Net income									213,600	245,300	221,500
Balance	1,208,100				994,500				1,208,100	994,500	749,200
Reportable Legal Entities | APIC
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock									0
Eliminations
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				(2,368,300)					(2,368,300)
Net income									(213,100)	(245,300)	(221,500)
Balance	(2,581,400)				(2,368,300)				(2,581,400)	(2,368,300)
Eliminations | Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				(100)				(100)	(100)	(100)	(100)
Balance	(100)				(100)				(100)	(100)	(100)
Eliminations | Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				0				0	0	0	0
Balance	0				0				0	0	0
Eliminations | APIC
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				(1,368,400)				(1,368,400)	(1,368,400)	(1,368,400)	(1,368,400)
Amounts related to share-based compensation											0
Balance	(1,368,400)				(1,368,400)				(1,368,400)	(1,368,400)	(1,368,400)
Eliminations | Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				(999,800)				(754,500)	(999,800)	(754,500)	(533,000)
Net income									(213,100)	(245,300)	(221,500)
Balance	(1,212,900)				(999,800)				(1,212,900)	(999,800)	(754,500)
Parent Company | Reportable Legal Entities
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				1,394,200					1,394,200
Net income									1,187,300	245,300	221,500
Balance	2,437,100				1,394,200				2,437,100	1,394,200
Parent Company | Reportable Legal Entities | Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				500				500	500	500	500
Balance	500				500				500	500	500
Parent Company | Reportable Legal Entities | Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				(806,500)				(608,000)	(806,500)	(608,000)	(294,100)
Issuance of common stock									(10,600)	(7,500)	(9,400)
Repurchase of common stock									(144,400)	(206,000)	(323,300)
Balance	(940,300)				(806,500)				(940,300)	(806,500)	(608,000)
Parent Company | Reportable Legal Entities | APIC
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				1,205,700				1,213,100	1,205,700	1,213,100	1,222,500
Issuance of common stock									10,600	7,400	9,400
Balance	1,195,100				1,205,700				1,195,100	1,205,700	1,213,100
Parent Company | Reportable Legal Entities | Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				994,500				749,200	994,500	749,200	527,700
Net income									1,187,300	245,300	221,500
Balance	2,181,800				994,500				2,181,800	994,500	749,200
Issuer | Reportable Legal Entities
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				1,506,100					1,506,100
Net income									(760,100)	245,300	221,500
Balance	745,700				1,506,100				745,700	1,506,100
Issuer | Reportable Legal Entities | Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				0				0	0	0	0
Balance	0				0				0	0	0
Issuer | Reportable Legal Entities | Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				0				0	0	0	0
Balance	0				0				0	0	0
Issuer | Reportable Legal Entities | APIC
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				573,100				571,100	573,100	571,100	564,500
Amounts related to share-based compensation									(9,400)	(5,600)	(2,700)
Share-based compensation expense									9,100	7,600	9,300
Balance	572,800				573,100				572,800	573,100	571,100
Issuer | Reportable Legal Entities | Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				933,000				687,700	933,000	687,700	466,200
Net income									(760,100)	245,300	221,500
Balance	172,900				933,000				172,900	933,000	687,700
Guarantor Subsidiaries | Reportable Legal Entities
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				52,100					52,100
Net income									(500)	0	0
Balance	51,600				52,100				51,600	52,100
Guarantor Subsidiaries | Reportable Legal Entities | Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				100				100	100	100	100
Balance	100				100				100	100	100
Guarantor Subsidiaries | Reportable Legal Entities | Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				0				0	0	0	0
Balance	0				0				0	0	0
Guarantor Subsidiaries | Reportable Legal Entities | APIC
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				52,000				52,000	52,000	52,000	52,000
Balance	52,000				52,000				52,000	52,000	52,000
Guarantor Subsidiaries | Reportable Legal Entities | Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				0				0	0	0	0
Net income									(500)	0	0
Balance	(500)				0				(500)	0	0
Non-Guarantor Subsidiaries | Reportable Legal Entities
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				154,300					154,300
Net income									0	0	0
Balance	154,300				154,300				154,300	154,300
Non-Guarantor Subsidiaries | Reportable Legal Entities | Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				0				0	0	0	0
Balance	0				0				0	0	0
Non-Guarantor Subsidiaries | Reportable Legal Entities | Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				0				0	0	0	0
Balance	0				0				0	0	0
Non-Guarantor Subsidiaries | Reportable Legal Entities | APIC
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				87,500				87,500	87,500	87,500	87,500
Amounts related to share-based compensation											0
Balance	87,500				87,500				87,500	87,500	87,500
Non-Guarantor Subsidiaries | Reportable Legal Entities | Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance				$ 66,800				$ 66,800	66,800	66,800	66,800
Net income									0	0	0
Balance	$ 66,800				$ 66,800				$ 66,800	$ 66,800	$ 66,800

Supplemental Quarterly Inform_3

Supplemental Quarterly Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Operating revenues	$ 3,501.7	$ 3,788	$ 3,829	$ 3,244.2	$ 3,379.5	$ 3,236.3	$ 3,211.2	$ 2,999.6	$ 14,362.9	$ 12,826.6	$ 11,594.6
Income (loss) from continuing operations before income taxes	100.5	57	69.1	47.3	51.2	108.8	89.9	(9.8)	273.9	240.1	352.1
Income (loss) from continuing operations	77.5	45	51.8	39.3	124.9	67.9	55.5	(3)	213.6	245.3	221.5
Net income (loss)	$ 77.5	$ 45	$ 51.8	$ 39.3	$ 124.9	$ 67.9	$ 55.5	$ (3)	$ 213.6	$ 245.3	$ 221.5
Income (loss) from continuing operations (per Common share)
Basic (in dollars per share)	$ 2.40	$ 1.40	$ 1.59	$ 1.17	$ 3.62	$ 1.92	$ 1.52	$ (0.08)	$ 6.54	$ 6.85
Diluted (in dollars per share)	2.38	1.38	1.58	1.16	3.58	1.90	1.51	(0.08)	6.48	6.78
Net income (loss) (per Common share)
Basic (in dollars per share)	2.40	1.40	1.59	1.17	3.62	1.92	1.52	(0.08)	6.54	6.85	$ 5.64
Diluted (in dollars per share)	$ 2.38	$ 1.38	$ 1.58	$ 1.16	$ 3.58	$ 1.90	$ 1.51	$ (0.08)	$ 6.48	$ 6.78	$ 5.59

Schedule II - Valuation And Q_2

Schedule II - Valuation And Qualifying Accounts (Details) - SEC Schedule, 12-09, Allowance, Credit Loss - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at January 1,	$ 1.1	$ 1.9	$ 2
Charged (Credited) to Expense	0.5	(0.8)	0
Deductions	(0.5)	0	(0.1)
Balance at December 31,	$ 1.1	$ 1.1	$ 1.9