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Acquisitions and Divestitures - Merger and Integration Expenses (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2021 | Sep. 30, 2020 | Sep. 30, 2021 | Sep. 30, 2020
Business Acquisition [Line Items] |  |  |  |
Merger and integration expense | $ 46 | $ 101 | $ 147 | $ 121
Personal expense |  |  |  |
Business Acquisition [Line Items] |  |  |  |
Merger and integration expense | 10 | 35 | 47 | 41
Legal and professional fees |  |  |  |
Business Acquisition [Line Items] |  |  |  |
Merger and integration expense | 9 | 31 | 15 | 38
Contribution expense |  |  |  |
Business Acquisition [Line Items] |  |  |  |
Merger and integration expense | 0 | 20 | 0 | 20
Other expense |  |  |  |
Business Acquisition [Line Items] |  |  |  |
Merger and integration expense | $ 27 | $ 15 | $ 85 | $ 22

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- Definition Costs incurred to effect a business combination which have been expensed during the period. Such costs could include business integration costs, systems integration and conversion costs, and severance and other employee-related costs. + References No definition available. + Details
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