We aggregate our operating units into three reportable segments: Refining, Logistics, and Retail. Operations that are not specifically included in the reportable segments are included in Corporate, Other and Eliminations, which consist of the following:  our corporate activities;  results of certain immaterial operating segments, including our Canadian crude trading operations (as discussed in Note 9 );  Alon's asphalt terminal operations; and  intercompany eliminations. Decisions concerning the allocation of resources and assessment of operating performance are made based on this segmentation. Management measures the operating performance of each of the reportable segments based on the segment contribution margin. Segment contribution margin is defined as net revenues less cost of materials and other and operating expenses, excluding depreciation and amortization. During the first quarter of 2020, we revised the structure of the internal financial information reviewed by management and began allocating the results of hedging activity associated with managing risks of our refineries, previously reported in corporate, other and eliminations, to our refining segment. The historical results of this hedging activity have been reclassified to conform to the current presentation. The assets and/or liabilities associated with this hedging activity have not been allocated to the refining segment. Refining Segment The refining segment processes crude oil and other feedstocks for the manufacture of transportation motor fuels, including various grades of gasoline, diesel fuel and aviation fuel, asphalt and other petroleum-based products that are distributed through owned and third-party product terminals. The refining segment has a combined nameplate capacity of 302,000 barrels per day ("bpd") as of March 31, 2020 , including the following:  75,000 bpd Tyler, Texas refinery (the "Tyler refinery");  80,000 bpd El Dorado, Arkansas refinery (the "El Dorado refinery");  73,000 bpd Big Spring, Texas refinery (the "Big Spring refinery");  74,000 bpd Krotz Springs, Louisiana refinery (the "Krotz Springs refinery"); and  a non-operating refinery located in Bakersfield, California. The refining segment also owns and operates three biodiesel facilities involved in the production of biodiesel fuels and related activities, located in Crossett, Arkansas, Cleburne, Texas and New Albany, Mississippi (acquired in October 2019). The biodiesel industry has historically been substantially aided by federal and state tax incentives. One tax incentive program that has been significant to our renewable fuels facilities is the federal blender's tax credit (also known as the biodiesel tax credit or "BTC"). The BTC provides a $1.00 refundable tax credit per gallon of pure biodiesel to the first blender of biodiesel with petroleum-based diesel fuel. The blender's tax credit was re-enacted in December 2019 for the years 2020 through 2022 and was retroactively reinstated for 2018 and 2019. The refining segment's petroleum-based products are marketed primarily in the south central, southwestern and western regions of the United States, and also ships and sells gasoline into wholesale markets in the southern and eastern United States. Motor fuels are sold under the Alon or Delek brand through various terminals to supply Alon or Delek branded retail sites. In addition, Alon sells motor fuels through its wholesale distribution network on an unbranded basis. Logistics Segment Our logistics segment owns and operates crude oil and refined products logistics and marketing assets. The logistics segment generates revenue by charging fees for gathering, transporting and storing crude oil and for marketing, distributing, transporting and storing intermediate and refined products in select regions of the southeastern United States and West Texas for our refining segment and third parties, and sales of wholesale products in the West Texas market. Retail Segment Our retail segment consists of 253 owned and leased convenience store sites as of March 31, 2020 , located primarily in central and West Texas and New Mexico. These convenience stores typically offer various grades of gasoline and diesel primarily under the Alon or Delek brand name and food products, food service, tobacco products, non-alcoholic and alcoholic beverages, general merchandise as well as money orders to the public, primarily under the 7-Eleven and Alon brand names. Substantially all of the motor fuel sold through our retail segment is supplied by our Big Spring refinery, which is transferred to the retail segment at prices substantially determined by reference to published commodity pricing information. In November 2018, we terminated the license agreement with 7-Eleven, Inc. and the terms of such termination require the removal of all 7-Eleven branding on a store-by-store basis by the earlier of December 31, 2021 or the date upon which our last 7-Eleven store is de-identified or closed. Merchandise sales at our convenience store sites will continue to be sold under the 7-Eleven brand name until 7-Eleven branding is removed at such convenience store sites pursuant to the termination. Significant Inter-segment Transactions All inter-segment transactions have been eliminated in consolidation and consist primarily of the following:  refining segment refined product sales to the retail segment to be sold through the store locations;  refining segment sales of asphalt and refined product to entities included in corporate, other and eliminations;  logistics segment service fee revenue under service agreements with the refining segment based on the number of gallons sold and to share a portion of the margin achieved in return for providing marketing, sales and customer services;  logistics segment sales of wholesale finished product to our refining segment; and  logistics segment crude transportation, terminalling and storage fee revenue from our refining segment for the utilization of pipeline, terminal and storage assets. Business Segment Operating Performance The following is a summary of business segment operating performance as measured by contribution margin for the period indicated (in millions): Three Months Ended March 31, 2020 (In millions) Refining Logistics Retail Corporate, Other and Eliminations Consolidated Net revenues (excluding inter-segment fees and revenues) $ 1,569.3 $ 56.8 $ 178.6 $ 16.5 $ 1,821.2 Inter-segment fees and revenues 158.6 106.6  (265.2 )  Operating costs and expenses: Cost of materials and other 1,906.6 101.3 144.1 (241.4 ) 1,910.6 Operating expenses (excluding depreciation and amortization presented below) 111.7 14.8 22.2 5.8 154.5 Segment contribution margin $ (290.4 ) $ 47.3 $ 12.3 $ (13.1 ) (243.9 ) Depreciation and amortization $ 37.2 $ 6.3 $ 2.9 $ 6.2 52.6 General and administrative expenses 65.7 Other operating income, net (0.7 ) Operating loss $ (361.5 ) Capital spending (excluding business combinations) $ 168.1 $ 3.0 $ 6.2 $ 12.9 $ 190.2 Three Months Ended March 31, 2019 Refining (1) Logistics Retail Corporate, Other and Eliminations (1) Consolidated Net revenues (excluding inter-segment fees and revenues) $ 1,907.4 $ 89.6 $ 197.2 $ 5.7 $ 2,199.9 Inter-segment fees and revenues 184.6 62.9  (247.5 )  Operating costs and expenses: Cost of materials and other 1,669.1 96.3 163.4 (229.4 ) 1,699.4 Operating expenses (excluding depreciation and amortization presented below) 121.0 16.1 23.6 6.0 166.7 Segment contribution margin $ 301.9 $ 40.1 $ 10.2 $ (18.4 ) 333.8 Depreciation and amortization $ 31.1 $ 6.5 $ 4.3 $ 4.9 46.8 General and administrative expenses 62.2 Other operating expense, net 2.4 Operating income $ 222.4 Capital spending (excluding business combinations) $ 81.7 $ 0.9 $ 5.1 $ 40.7 $ 128.4 (1) The refining segment results of operations for the three months ended March 31, 2019 , includes hedging gains, a component of cost of materials and other, of $7.6 million which was previously included and reported in corporate, other and eliminations. Other Segment Information Total assets by segment were as follows as of March 31, 2020 : Refining Logistics Retail Corporate, Other and Eliminations Consolidated Total assets $ 5,949.5 $ 946.3 $ 312.1 $ (1,114.5 ) $ 6,093.4 Less: Inter-segment notes receivable (1,584.3 )   1,584.3  Inter-segment right of use lease assets (418.1 )   418.1  Total assets, excluding inter-segment notes receivable and right of use assets $ 3,947.1 $ 946.3 $ 312.1 $ 887.9 $ 6,093.4 Property, plant and equipment and accumulated depreciation as of March 31, 2020 and depreciation expense by reporting segment for the three months ended March 31, 2020 are as follows (in millions): Refining Logistics Retail Corporate, Other and Eliminations Consolidated Property, plant and equipment $ 2,601.8 $ 665.7 $ 162.7 $ 109.6 $ 3,539.8 Less: Accumulated depreciation (684.3 ) (186.2 ) (39.4 ) (65.5 ) (975.4 ) Property, plant and equipment, net $ 1,917.5 $ 479.5 $ 123.3 $ 44.1 $ 2,564.4 Depreciation expense for the three months ended March 31, 2020 $ 35.6 $ 6.3 $ 2.7 $ 6.2 $ 50.8 In accordance with Accounting Standards Codification ("ASC") 360, Property, Plant and Equipment ("ASC 360"), Delek evaluates the realizability of property, plant and equipment as events occur that might indicate potential impairment. There were no indicators of impairment related to our property, plant and equipment as of March 31, 2020 (see Note 1 for further discussion on the impact of COVID-19 Pandemic and OPEC Production Disputes).