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Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions | Total | Common Stock | Additional Paid-in Capital | Retained Earnings | Accumulated Other Comprehensive Income (Loss) | Treasury Stock | Notes Receivable for the Issuance of Common Stock
--- | --- | --- | --- | --- | --- | --- | ---
Total stockholder's equity at beginning of period at Dec. 31, 2014 |  | $ 683 | $ 2,151 | $ 9,645 | $ 400 | $ (84) | $ (1)
Increase (Decrease) in Stockholders' Equity [Roll Forward] |  |  |  |  |  |  |
Stock-based compensation |  |  | 2 |  |  | 6 |
Dividends paid to common stockholders |  |  |  | (811) |  |  |
Net income | $ 479 |  |  | 479 |  |  |
Other comprehensive income (loss) | (715) |  |  |  | (715) |  |
Decrease in notes receivable for common stock |  |  |  |  |  |  | 1
Total stockholder's equity at end of period at Dec. 31, 2015 | 11,756 | 683 | 2,153 | 9,313 | (315) | (78) | 0
Increase (Decrease) in Stockholders' Equity [Roll Forward] |  |  |  |  |  |  |
Stock-based compensation |  |  | 20 |  |  | 5 |
Dividends paid to common stockholders |  |  |  | (813) |  |  |
Net income | 859 |  |  | 859 |  |  |
Other comprehensive income (loss) | 142 |  |  |  | 142 |  |
Decrease in notes receivable for common stock |  |  |  |  |  |  | 0
Total stockholder's equity at end of period at Dec. 31, 2016 | 11,969 | 683 | 2,173 | 9,359 | (173) | (73) | 0
Increase (Decrease) in Stockholders' Equity [Roll Forward] |  |  |  |  |  |  |
Stock-based compensation |  |  | 2 |  |  | 13 |
Dividends paid to common stockholders |  |  |  | (844) |  |  |
Net income | 899 |  |  | 899 |  |  |
Other comprehensive income (loss) | 205 |  |  |  | 205 |  |
Decrease in notes receivable for common stock |  |  |  |  |  |  | $ 0
Total stockholder's equity at end of period at Dec. 31, 2017 | $ 12,244 | $ 683 | $ 2,175 | $ 9,414 | $ 32 | $ (60) |

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