Financial Instruments and Fair Value - Estimated Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Prepayments and other current assets \| Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other financial instruments in asset positions	$ 45	$ 1

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

Name:	us-gaap_AssetsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant