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Stockholders' Equity (Details) - USD ($) $ in Millions | 12 Months Ended |  |  |
--- | --- | --- | --- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018 | Aug. 31, 2018 | Nov. 20, 2015 | Nov. 30, 2014
Class of Stock [Line Items] |  |  |  |  |  |
Dividends, Common Stock, Cash | $ 137 | $ 132 | $ 120 |  |  |
Common Stock, Voting Rights, Number of Votes Per Share | one |  |  |  |  |
Stock repurchase program, authorized amount |  |  |  | $ 150 | $ 150 | $ 250
Stock Repurchase Program, Shares Repurchased, Gross | 7,075,720 |  |  |  |  |
Treasury Stock Purchase Price, Repurchase Program | $ 419 |  |  |  |  |
Ordinary Dividend [Member] |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |
Dividends, Common Stock, Cash | $ 137 | $ 132 | $ 120 |  |  |
Treasury Stock [Member] |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |
Stock repurchased 2014 program, shares repurchase | 995,529 | 517,712 | 1,368,881 |  |  |

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