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Shareholders' Equity - Additional Information (Details) - USD ($) | 3 Months Ended | 96 Months Ended |  |  |
--- | --- | --- | --- | --- | ---
Mar. 31, 2020 | Mar. 31, 2019 | Mar. 31, 2020 | Feb. 28, 2017 | Nov. 30, 2014 | Apr. 30, 2012
Equity, Class of Treasury Stock [Line Items] |  |  |  |  |  |
Total cost of shares purchased | $ 463,000,000 | $ 101,000,000 |  |  |  |
Number of shares excluded from the calculation of diluted earnings per share (in shares) | 0 | 100,000 |  |  |  |
2012 - Share Repurchase Program |  |  |  |  |  |
Equity, Class of Treasury Stock [Line Items] |  |  |  |  |  |
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 | $ 5,000,000,000.0
Share repurchase, remaining authorization limit (in shares) | $ 1,600,000,000 |  | $ 1,600,000,000 |  |  |
Shares purchased (in shares) | 2,200,000 | 600,000 | 130,900,000 |  |  |
Total cost of shares purchased | $ 461,000,000 | $ 100,000,000 | $ 13,400,000,000 |  |  |

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- Definition Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257 + Details
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