Debt - Standby Letters of Credit (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Debt Disclosure [Abstract]
Letters of credit, amount outstanding	$ 631	$ 113

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

No definition available.

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