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Acquisitions and Dispositions of Businesses - Dispositions (Details) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2019 USD ($) disposal | Sep. 30, 2018 USD ($) disposal | Sep. 30, 2019 USD ($) disposal | Sep. 30, 2018 USD ($) disposal
Dispositions |  |  |  |
Pretax gains (losses) recognized on disposal of businesses | $ | $ 1 | $ (3) | $ 8 | $ (4)
Disposal Group, Not Discontinued Operations |  |  |  |
Dispositions |  |  |  |
Number of dispositions | disposal | 2 | 2 | 6 | 3

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- Definition Amount before tax of gain (loss) recognized on the sale or disposal of a disposal group. Excludes discontinued operations. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=109226348&loc=d3e2443-110228 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=109226691&loc=d3e2941-110230 + Details
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