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v3.20.4

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

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