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CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED) - USD ($) shares in Millions, $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2021 | Sep. 30, 2020 | Sep. 30, 2021 | Sep. 30, 2020
Operating revenues |  |  |  |
Electric | $ 3,176 | $ 2,941 | $ 8,643 | $ 7,430
Natural gas | 268 | 219 | 1,364 | 1,082
Other | 23 | 22 | 69 | 67
Total operating revenues | 3,467 | 3,182 | 10,076 | 8,579
Operating expenses |  |  |  |
Electric fuel and purchased power | 1,210 | 981 | 3,643 | 2,611
Cost of natural gas sold and transported | 86 | 54 | 603 | 425
Cost of sales — other | 11 | 11 | 28 | 28
Operating and maintenance expenses | 568 | 579 | 1,752 | 1,708
Conservation and demand side management expenses | 78 | 73 | 222 | 215
Depreciation and amortization | 537 | 513 | 1,586 | 1,449
Taxes, Other | 152 | 158 | 472 | 453
Total operating expenses | 2,642 | 2,369 | 8,306 | 6,889
Operating income | 825 | 813 | 1,770 | 1,690
Other (expense) income, net | (3) | 1 | 5 | (6)
Earnings from equity method investments | 13 | 12 | 47 | 29
Allowance for funds used during construction — equity | 21 | 30 | 53 | 91
Interest charges and financing costs |  |  |  |
Interest charges — includes other financing costs of $7, $7, $22 and $21, respectively | 211 | 221 | 628 | 628
Allowance for funds used during construction — debt | (7) | (11) | (18) | (33)
Total interest charges and financing costs | 204 | 210 | 610 | 595
Income before income taxes | 652 | 646 | 1,265 | 1,209
Income tax expense (benefit) | 43 | 43 | (17) | 24
Net income | $ 609 | $ 603 | $ 1,282 | $ 1,185
Weighted average common shares outstanding: |  |  |  |
Basic (in shares) | 539 | 526 | 539 | 526
Diluted (in shares) | 539 | 528 | 539 | 527
Earnings per average common share: |  |  |  |
Basic (in dollars per share) | $ 1.13 | $ 1.15 | $ 2.38 | $ 2.25
Diluted (in dollars per share) | $ 1.13 | $ 1.14 | $ 2.38 | $ 2.25

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