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Shareholders' Equity - Ordinary Shares (Details) - USD ($) $ / shares in Units, shares in Millions | 1 Months Ended | 12 Months Ended | 81 Months Ended |  |  |
--- | --- | --- | --- | --- | --- | ---
Jan. 31, 2018 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2018 | Feb. 28, 2017 | Nov. 30, 2014 | Apr. 30, 2012
Common Stock Programs |  |  |  |  |  |  |  |
Number of shares repurchased (in shares) |  |  |  |  | 118.3 |  |  |
Costs recorded to retained earnings |  |  |  |  |  |  |  |
Total repurchase cost |  | $ 1,454,000,000 | $ 2,415,000,000 | $ 1,257,000,000 | $ 11,000,000,000 |  |  |
Share Repurchase Program of 2012 |  |  |  |  |  |  |  |
Common Stock Programs |  |  |  |  |  |  |  |
Share repurchase authorization limit |  |  |  |  |  |  |  | $ 5,000,000,000.0
Number of shares repurchased (in shares) | 0.1 | 10.0 | 18.0 |  |  |  |  |
Average price per share (in dollars per share) | $ 134.41 | $ 143.94 | $ 133.67 |  |  |  |  |
Costs recorded to retained earnings |  |  |  |  |  |  |  |
Total repurchase cost | $ 15,900,000 | $ 1,447,000,000 | $ 2,403,000,000 |  |  |  |  |
Additional associated costs |  | 7,000,000 | 12,000,000 |  |  |  |  |
Total costs recorded to retained earnings |  | 1,454,000,000 | $ 2,415,000,000 |  |  |  |  |
Share Repurchase Program of 2014 |  |  |  |  |  |  |  |
Common Stock Programs |  |  |  |  |  |  |  |
Share repurchase authorization limit |  | 15,000,000,000.0 |  |  | 15,000,000,000.0 |  | $ 5,000,000,000.0 |
Share Repurchase Program of 2017 |  |  |  |  |  |  |  |
Common Stock Programs |  |  |  |  |  |  |  |
Share repurchase authorization limit |  |  |  |  |  | $ 5,000,000,000.0 |  |
Costs recorded to retained earnings |  |  |  |  |  |  |  |
Remaining authorized repurchase amount |  | $ 4,000,000,000 |  |  | $ 4,000,000,000 |  |  |

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