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Acquisitions and Dispositions of Businesses - Dispositions (Details) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2021 USD ($) disposition | Jun. 30, 2020 USD ($) disposition | Jun. 30, 2021 USD ($) disposition | Jun. 30, 2020 USD ($) disposition
Business Combination and Asset Acquisition [Abstract] |  |  |  |
Number of dispositions | disposition | 1 | 0 | 1 | 1
Pretax gains (losses) recognized on disposal of businesses | $ | $ 1 | $ 0 | $ 1 | $ 25

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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=123351718&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=123570139&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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