Receivables - Schedule of Allowance for Doubtful Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Customer receivables
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at beginning of year	$ 8	$ 13	$ 8
Provision for doubtful accounts	2	1	7
Write off of uncollectible accounts	(2)	(5)	(3)
Recoveries of prior write-offs	0	0	(1)
Other	(4)	(1)	2
Balance at end of year	4	8	13
Other receivables
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at beginning of year	34	32	34
Provision for doubtful accounts	7	9	6
Write off of uncollectible accounts	(2)	(1)	(1)
Recoveries of prior write-offs	(3)	(3)	1
Other	(5)	(3)	(8)
Balance at end of year	$ 31	$ 34	$ 32