Other liabilities - Balance sheet presentation (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Other Liabilities [Abstract]
Other current liabilities	$ 316	$ 322
Other non-current liabilities	120	128
Total Other Liabilities	$ 436	$ 450

Amount of expenses incurred but not yet paid classified as other, due within one year or the normal operating cycle, if longer.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
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Name:	us-gaap_OtherAccruedLiabilitiesCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant