The following table presents information on our business segments. Three Months Ended June 30 Six Months Ended June 30 Millions of dollars 2020 2019 2020 2019 Revenue: Completion and Production $ 1,672 $ 3,805 $ 4,634 $ 7,467 Drilling and Evaluation 1,524 2,125 3,599 4,200 Total revenue $ 3,196 $ 5,930 $ 8,233 $ 11,667 Operating income (loss): Completion and Production $ 159 $ 470 $ 504 $ 838 Drilling and Evaluation 127 145 344 268 Total operations 286 615 848 1,106 Corporate and other (a) (50) (65) (110) (130) Impairments and other charges (b) (2,147) (247) (3,220) (308) Total operating income (loss) $ (1,911) $ 303 $ (2,482) $ 668 Interest expense, net of interest income (124) (144) (258) (287) Loss on early extinguishment of debt (c)   (168)  Other, net (48) (8) (71) (38) Income (loss) before income taxes $ (2,083) $ 151 $ (2,979) $ 343 (a) Includes certain expenses not attributable to a particular business segment, such as costs related to support functions and corporate executives, and also includes amortization expense associated with intangible assets recorded as a result of acquisitions. (b) For the three months ended June 30, 2020, amount includes approximately $1.4 billion attributable to Completion and Production, $770 million attributable to Drilling and Evaluation, and $25 million attributable to Corporate and other. For the three months ended June 30, 2019, amount includes $77 million attributable to Completion and Production, $142 million attributable to Drilling and Evaluation, and $28 million attributable to Corporate and other. For the six months ended June 30, 2020, amount includes $2.1 billion attributable to Completion and Production, $1.0 billion attributable to Drilling and Evaluation, and $41 million attributable to Corporate and other. For the six months ended June 30, 2019, amount includes $127 million attributable to Completion and Production, $153 million attributable to Drilling and Evaluation, and $28 million attributable to Corporate and other. See Note 2 for further discussion on these impairments and other charges. (c) For the six months ended June 30, 2020, amount includes a $168 million loss on extinguishment of debt related to the early repurchase of senior notes. See Note 6 for further discussion on this charge.