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Share-Based Compensation Plans - Share-based compensation expense recognized in continuing operations (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Total share-based compensation expense | $ 449 | $ 312 | $ 317
Tax benefit | 87 | 61 | 66
Share-based compensation expense, net of tax | 362 | 251 | 251
Employee share purchase plans and other |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Total share-based compensation expense | 56 | 10 | 9
Restricted share units |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Total share-based compensation expense | 204 | 186 | 198
Performance share awards |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Total share-based compensation expense | $ 189 | $ 116 | $ 110

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