Earnings Per Share (Details) - shares shares in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Earnings Per Share
Outstanding options to purchase shares of stock excluded from the diluted earnings per share calculation	1.1	4.4
Calculation of diluted weighted-average shares outstanding
Basic weighted-average shares outstanding	414.3	437.7
Common stock equivalents	4.0	2.2
Diluted weighted-average shares outstanding	418.3	439.9

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.

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The sum of dilutive potential common shares or units used in the calculation of the diluted per-share or per-unit computation.

+ References

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

+ 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
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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