Fair Value Measurements and Financial Instruments - Schedule of financial instruments where the carrying amounts and fair values differ (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Carrying Value
Fair value of financial instrument
Long-term debt	$ 5,990	$ 5,993
Fair Value \| Fair Value, Inputs, Level 2
Fair value of financial instrument
Long-term debt	$ 6,344	$ 6,159

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

No definition available.

Name:	us-gaap_LongTermDebtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant