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CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Millions, $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Operating revenues |  |  |
Total operating revenues | $ 11,537 | $ 11,404 | $ 11,107
Operating expenses |  |  |
Electric fuel and purchased power | 3,854 | 3,757 | 3,718
Cost of natural gas sold and transported | 843 | 823 | 733
Cost of sales — other | 35 | 34 | 36
Operating and maintenance expenses | 2,352 | 2,270 | 2,300
Conservation and demand side management program expenses | 290 | 273 | 245
Depreciation and amortization | 1,642 | 1,479 | 1,303
Taxes (other than income taxes) | 556 | 545 | 532
Total operating expenses | 9,572 | 9,181 | 8,867
Operating income | 1,965 | 2,223 | 2,240
Other income, net | (14) | (10) | (18)
Income (Loss) from Equity Method Investments | 35 | 30 | 42
Allowance for funds used during construction — equity | 108 | 75 | 60
Interest charges and financing costs |  |  |
Interest charges — includes other financing costs of $25, $24 and $25, respectively | 700 | 663 | 647
Allowance for funds used during construction — debt | (48) | (35) | (27)
Total interest charges and financing costs | 652 | 628 | 620
Income before income taxes | 1,442 | 1,690 | 1,704
Income taxes | 181 | 542 | 581
Net income | $ 1,261 | $ 1,148 | $ 1,123
Weighted average common shares outstanding: |  |  |
Basic (in shares) | 511 | 509 | 509
Diluted (in shares) | 511 | 509 | 509
Earnings per average common share: |  |  |
Basic (in dollars per share) | $ 2.47 | $ 2.26 | $ 2.21
Diluted (in dollars per share) | $ 2.47 | $ 2.25 | $ 2.21
Electricity, US Regulated [Member] |  |  |
Operating revenues |  |  |
Total operating revenues | $ 9,719 | $ 9,676 | $ 9,500
Natural Gas, US Regulated [Member] |  |  |
Operating revenues |  |  |
Total operating revenues | 1,739 | 1,650 | 1,531
Product and Service, Other [Member] |  |  |
Operating revenues |  |  |
Total operating revenues | $ 79 | $ 78 | $ 76

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