Financial Instruments and Fair Value Measures - Summary of Financial Assets and Liabilities Not Carried at Fair Value (Details) $ in Millions	Sep. 30, 2019 USD ($)
Carrying Value [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term debt and related current maturities	$ 1,481
Fair Value [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Long-term debt and related current maturities	$ 1,492