Financial Instruments and Risk Concentration - Schedule of Accounts Receivable Allowances (Details) - Allowance for doubtful accounts, current - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year	$ 17	$ 7	$ 12
Amounts charged (credited) to operating results	(9)	10	(5)
Recoveries and write-offs, net	0	0	0
Balance at end of year	$ 8	$ 17	$ 7