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Shareholders' Equity (Details) - USD ($) | 1 Months Ended | 3 Months Ended | 6 Months Ended | 72 Months Ended |  |  |
--- | --- | --- | --- | --- | --- | --- | ---
Jul. 31, 2017 | Jun. 30, 2018 | Jun. 30, 2017 | Jun. 30, 2018 | Jun. 30, 2017 | Mar. 31, 2018 | Feb. 28, 2017 | Nov. 30, 2014 | Apr. 30, 2012
Common Stock Programs |  |  |  |  |  |  |  |  |
Shares purchased (in shares) |  |  |  |  |  | 115,000,000 |  |  |
Total cost of shares purchased |  |  |  | $ 955,000,000 | $ 1,160,000,000 | $ 10,500,000,000 |  |  |
Weighted average shares outstanding |  |  |  |  |  |  |  |  |
Basic weighted average ordinary shares outstanding (in shares) |  | 246,000,000 | 262,400,000 | 247,200,000 | 263,600,000 |  |  |  |
Dilutive effect of potentially issuable shares (in shares) |  | 1,400,000 | 0 | 1,600,000 | 2,100,000 |  |  |  |
Diluted weighted average ordinary shares outstanding (in shares) |  | 247,400,000 | 262,400,000 | 248,800,000 | 265,700,000 |  |  |  |
Number of shares excluded from the calculation of diluted earnings per share (in shares) |  | 0 | 1,900,000 | 0 | 200,000 |  |  |  |
Share Repurchase Program of 2014 |  |  |  |  |  |  |  |  |
Common Stock Programs |  |  |  |  |  |  |  |  |
Share repurchase authorization limit (up to) |  | $ 15,000,000,000.0 |  | $ 15,000,000,000.0 |  |  | $ 5,000,000,000.0 | $ 5,000,000,000.0 |
Share repurchase, remaining authorization limit (in shares) |  | $ 4,500,000,000 |  | $ 4,500,000,000 |  |  |  |  |
2012 - Share Repurchase Program |  |  |  |  |  |  |  |  |
Common Stock Programs |  |  |  |  |  |  |  |  |
Share repurchase authorization limit (up to) |  |  |  |  |  |  |  |  | $ 5,000,000,000.0
Shares purchased (in shares) | 500,000 | 2,800,000 | 8,000,000 | 6,700,000 | 9,100,000 |  |  |  |
Total cost of shares purchased | $ 60,000,000 | $ 400,000,000 | $ 1,030,000,000 | $ 950,000,000 | $ 1,154,000,000 |  |  |  |

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