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Derivatives and Hedging - Narrative (Details) € in Millions, $ in Millions |  | 12 Months Ended
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Dec. 31, 2018 USD ($) | Dec. 31, 2018 EUR (€) | Dec. 31, 2018 USD ($) | Dec. 31, 2017 USD ($) | Dec. 31, 2016 USD ($)
Derivative [Line Items] |  |  |  |  |
Estimated pretax losses currently included within Accumulated Other Comprehensive Loss that will be reclassified to earnings in next twelve months |  |  | $ 13 |  |
Gain (loss) recognized in income on ineffective portion of derivatives |  |  | 0 | $ 0 | $ 0
Financial instruments |  |  | $ (49) | 2 | $ (14)
Not accounted for as hedges |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Maximum length of time hedged in foreign currency undesignated hedge (in years) |  |  | 1 year |  |
Gross foreign exchange contracts | Not accounted for as hedges |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Financial instruments |  |  | $ 27 | $ 7 |
Cash Flow Hedging |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Foreign currency exposures, maximum average hedging period ( in years) |  |  | 2 years |  |
Net Investment Hedging |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Outstanding Euro-denominated commercial paper | $ 250 | € 220 |  |  |
Unrealized gain recognized in AOCI |  |  | $ 21 |  |

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- Definition Represents the estimated net amount of unrealized gains (losses) on hedges at the reporting date expected to be reclassified to earnings within the next 12 months. + References No definition available. + Details
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- Definition Maximum length of time over which the entity is hedging its exposure to the variability in future exchange rates using instruments not designated as accounting hedges. + References No definition available. + Details
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- Definition Amount of increase (decrease) in the fair value of derivatives recognized in the income statement. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5618551-113959 + Details
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- Definition The portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments representing (a) the amount of the hedge ineffectiveness and (b) the amount, if any, excluded from the assessment of hedge effectiveness. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624171-113959 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 25 -Section 50 -Paragraph 1 -Subparagraph (a)(1),(2) -URI http://asc.fasb.org/extlink&oid=109977999&loc=d3e76258-113986 + Details
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- Definition Amount before tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 20 -Section 35 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=82918529&loc=d3e30304-110892 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 30 -Section 45 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=109240241&loc=d3e32022-110900 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 30 -Section 45 -Paragraph 20 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109240241&loc=d3e32211-110900 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=114867106&loc=d3e637-108580 Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 10A -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=114867106&loc=SL7669646-108580 + Details
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