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Financial Instruments and Fair Value Measurements - Narrative (Details) | 9 Months Ended
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Sep. 30, 2019
Fair Value [Line Items] |
Equity stake in Azul | 2.00%
Preferred Stock |
Fair Value [Line Items] |
Equity stake in Azul | 8.00%
Asset-Backed Securities | Minimum |
Fair Value [Line Items] |
Available-for-sale securities remaining maturities | 1 year
Asset-Backed Securities | Maximum |
Fair Value [Line Items] |
Available-for-sale securities remaining maturities | 15 years
Corporate Debt | Maximum |
Fair Value [Line Items] |
Available-for-sale securities remaining maturities | 3 years
CDARS | Maximum |
Fair Value [Line Items] |
Available-for-sale securities remaining maturities | 1 year
U.S. Government and Agency Notes | Minimum |
Fair Value [Line Items] |
Available-for-sale securities remaining maturities | 3 years
Other Fixed-Income Securities | Maximum |
Fair Value [Line Items] |
Available-for-sale securities remaining maturities | 2 years

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