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Acquisitions and Dispositions of Businesses - Acquisitions (Details) $ in Millions | 9 Months Ended |
--- | --- | ---
Sep. 30, 2019 USD ($) acquisition | Sep. 30, 2018 acquisition | Dec. 31, 2018 USD ($)
Business Acquisition [Line Items] |  |  |
Number of business acquired under business combination | acquisition | 3 | 5 |
Assets acquired |  |  |
Goodwill | $ 8,071 |  | $ 8,171
2019 Acquisitions |  |  |
Business Combination, Consideration Transferred [Abstract] |  |  |
Consideration Transferred | 42 |  |
Deferred and contingent consideration | 8 |  |
Aggregate consideration transferred | 50 |  |
Assets acquired |  |  |
Cash and cash equivalents | 4 |  |
Receivables, net | 1 |  |
Goodwill | 33 |  |
Intangible assets, net | 22 |  |
Fixed assets, net | 1 |  |
Other assets | 13 |  |
Total assets acquired | 74 |  |
Liabilities assumed |  |  |
Current liabilities | 18 |  |
Other non-current liabilities | 6 |  |
Total liabilities assumed | 24 |  |
Net assets acquired | $ 50 |  |

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