ITEM 6. SELECTED FINANCIAL DATA Selected financial data set forth below are derived from our audited Consolidated Financial Statements for the periods indicated (in millions, except per share data). The financial data should be read in conjunction with Management’s Discussion and Analysis of Financial Condition and Results of Operations and our Consolidated Financial Statements and the accompanying notes thereto included elsewhere in this report. Year Ended December 31, 2019 2018 2017 2016 2015 Consolidated Statement of Operations Data: Revenues $ 9,730 $ 7,987 $ 5,601 $ 1,283 $ 271 Income (loss) from operations 2,361 2,024 1,388 (30 ) (449 ) Interest expense, net of capitalized interest (1,432) (875) (747) (488) (322) Net income (loss) attributable to common stockholders 648 471 (393 ) (610 ) (975 ) Common Stock Data: Net income (loss) per share attributable to common stockholders—basic $ 2.53 $ 1.92 $ (1.68 ) $ (2.67 ) $ (4.30 ) Net income (loss) per share attributable to common stockholders—diluted $ 2.51 $ 1.90 $ (1.68) $ (2.67) $ (4.30) Weighted average number of common shares outstanding —basic 256.2 245.6 233.1 228.8 226.9 Weighted average number of common shares outstanding —diluted 258.1 248.0 233.1 228.8 226.9 December 31, 2019 2018 2017 2016 2015 Consolidated Balance Sheet Data: Property, plant and equipment, net $ 29,673 $ 27,245 $ 23,978 $ 20,635 $ 16,194 Total assets 35,492 31,987 27,906 23,703 18,809 Current debt, net — 239 — 247 1,673 Long-term debt, net 30,774 28,179 25,336 21,688 14,920 40