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Derivatives and Hedging - Narrative (Details) € in Millions, $ in Millions |  | 12 Months Ended
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Dec. 31, 2019 EUR (€) | Dec. 31, 2019 USD ($) | Dec. 31, 2019 USD ($) | Dec. 31, 2018 EUR (€) | Dec. 31, 2018 USD ($) | Dec. 31, 2017 USD ($)
Derivative [Line Items] |  |  |  |  |  |
Estimated pretax losses currently included within Accumulated Other Comprehensive Loss that will be reclassified to earnings in next twelve months |  |  | $ 11 |  |  |
Financial instruments |  |  | $ (34) |  | $ (49) | $ 2
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] |  |  |  |  |  |
Derivative term of contract (in days) |  |  | 30 days |  |  |
Financial instruments |  |  | $ (18) |  | (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 | € 101 | $ 112 |  | € 220 | 250 |
Unrealized gain recognized in AOCI |  |  | $ 29 |  | $ 21 |

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