Basis of Presentation - Changes in Allowances for Credit Losses (Details) $ in Millions	6 Months Ended
	Jun. 30, 2020 USD ($)
Allowance for Trade Receivables
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at January 1, 2020	$ (35)
Current period provision for expected credit losses	(7)
Write-offs charged against the allowance	0
Currency	2
Balance at June 30, 2020	(40)
Allowance for Other Current Receivables
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at January 1, 2020	(44)
Current period provision for expected credit losses	(1)
Write-offs charged against the allowance	2
Currency	3
Balance at June 30, 2020	(40)
Allowance for Long-Term Receivables
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at January 1, 2020	(14)
Current period provision for expected credit losses	(2)
Write-offs charged against the allowance	0
Currency	4
Balance at June 30, 2020	$ (12)