Investments - Schedule of maturities for short-term investments (Details) $ in Millions	Sep. 30, 2018 USD ($)
Short-Term Investments by Contractual Maturity:
Due in one year or less	$ 226
Due after one year through three years	228
Due after three years through five years	6
Due after five years	18
Total	$ 478

Available-For-Sale Securities, Debt Maturities, After Five Years, Fair Value

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Available-For-Sale Securities, Debt Maturities, After One Year Through Three Years, Fair Value

+ References

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Available-For-Sale Securities, Debt Maturities, After Three Years Through Five Years, Fair Value

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Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), maturing in next fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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