Supplemental Financial Information - Accounts Receivable (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Accounts Receivable, after Allowance for Credit Loss, Current [Abstract]
Accounts receivable	$ 1,534	$ 1,387
Less: allowance for doubtful accounts	(44)	(31)
Total accounts receivable, net	1,490	1,356
Trade [Member]
Accounts Receivable, after Allowance for Credit Loss, Current [Abstract]
Accounts receivable	1,482	1,364
Other [Member]
Accounts Receivable, after Allowance for Credit Loss, Current [Abstract]
Accounts receivable	$ 52	$ 23