Revenues Revenue Recognition Venezuela (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2019	Jan. 01, 2018
Other Non-current Assets		$ 139	$ 365
Accounts Receivable, after Allowance for Credit Loss, Current			1,089	$ 1,051
Accounts Receivable, Net of Allowance for Uncollectible Accounts of $0 at December 31, 2019 and $123 at December 31, 2018		1,130	$ 1,241
Accounts Receivable, Allowance for Credit Loss, Recovery		(16)
VENEZUELA | Revenue Recognition [Member]
Cumulative Effect of Change in Accounting Estimate	$ 230
Other Non-current Assets		158
Accounts Receivable, Net of Allowance for Uncollectible Accounts of $0 at December 31, 2019 and $123 at December 31, 2018		$ 72