Revenues and Accounts Receivable - Trade Accounts Receivable and Other Receivables (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Substantially all trade accounts receivable, net, maximum age of balances past their scheduled invoice date	30 days	30 days
Allowance for doubtful accounts receivable	$ 3	$ 3
Trade accounts receivable arising from revenues from contracts with customers	2,628	2,277
Other trade accounts receivables and other receivables (1)	3,076	2,732
Impact due to contractual rights of offset with counterparties	(2,792)	(2,555)
Trade accounts receivable and other receivables, net	$ 2,912	$ 2,454