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Schedule II - Valuation Accounts and Reserves - Valuation Accounts and Reserves (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Allowance for Doubtful Accounts [Member] |  |  |
Balance at beginning of period | $ 60 | $ 59 | $ 48
Additions | 4 | 1 | 11
Balance at end of period | 64 | 60 | 59
Valuation Allowance of Deferred Tax Assets [Member] |  |  |
Balance at beginning of period | 456 | 270 | 238
Additions | 17 | 241 | 55
Net deductions and other | 156 | 55 | 23
Balance at end of period | $ 317 | 456 | 270
Business Restructuring Reserves [Member] |  |  |
Balance at beginning of period |  | 5 | 3
Additions |  |  | 15
Net deductions and other |  | $ 5 | 13
Balance at end of period |  |  | $ 5

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- Definition Total of the additions in a given period to allowances and reserves. + References No definition available. + Details
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- Definition Amount of valuation and qualifying accounts and reserves. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 4 -Subparagraph (SX 210.12-09) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690 + Details
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- Definition Amount of decrease in valuation and qualifying accounts and reserves. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 4 -Subparagraph (SX 210.12-09) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690 + Details
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