Schedule II - Valuation and Qualifying Accounts and Allowances (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016		Dec. 31, 2015
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Bad Debt Expense	$ 5	$ 8	$ 69
Inventory Valuation Reserves	305	635	265		$ 288
Accounts Receivable, Net of Allowance for Uncollectible Accounts of $123 in 2018 and $156 in 2017	1,130	1,103
SEC Schedule, 12-09, Allowance, Credit Loss [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
of Period	329	129	113
Expense (a)		238	69
Recoveries (b)	(17)	0	0
Other (c) (d)	(23)	(38)	(53)
Period	294	329	129
Valuation allowance on deferred tax assets [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
of Period	1,887	1,738	868
Expense (a)	(166)	158	872
Recoveries (b)	0	0	0
Other (c) (d)	(19)	(9)	(2)	[1]
Period	1,702	1,887	1,738
SEC Schedule, 12-09, Reserve, Inventory [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Expense (a)	86	545	273
Recoveries (b)	(6)	(5)	(4)
Other (c) (d)	(410)	(170)	(292)
Short [Member] | SEC Schedule, 12-09, Allowance, Credit Loss [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
of Period	156	129
Expense (a)	5	80
Recoveries (b)	(15)	0
Other (c) (d)	(23)	(53)
Period	123	156	129
Long [Member] | SEC Schedule, 12-09, Allowance, Credit Loss [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
of Period	173	0
Expense (a)	0	158
Recoveries (b)	(2)	0
Other (c) (d)	0	15
Period	$ 171	$ 173	$ 0

[1] (a)In the second quarter of 2017, we changed the accounting for revenue with our primary customer in Venezuela to record a discount reflecting the time value of money and accrete the discount as interest income over the expected collection period using the effective interest method. In the fourth quarter of 2017, we changed the accounting for revenue with substantially all of our customers in Venezuela due to the downgrade of the country’s bonds by certain credit agencies, continued economic turmoil and continued economic sanctions around certain financing transactions imposed by the U.S. government. We recorded a charge equal to a full allowance on our accounts receivable for customers in Venezuela of approximately $230 million. This reduced our long-term and current receivables by $158 million and $72 million, respectively, as of December 31, 2017. The long-term allowance related to our primary customer in Venezuela is $171 million and $173 million as of December 31, 2018 and December 31, 2017.(b)Of the total recoveries, we collected $16 million on previously fully reserved Venezuelan accounts receivable.(c)Other within the allowance for uncollectible accounts receivable as of December 2017 includes write-offs and amounts reclassified to long-term and as of December 31, 2018, includes reductions to allowance reserves.(d)Other for valuation allowance on deferred taxes is primarily due to currency translation. Other for excess and obsolete inventory reserve primarily represents the removal of scrapped inventory that had been previously reserved.All other schedules are omitted because they are not required or because the information is included in the financial statements or the related notes.