Receivables (Details) $ in Millions		3 Months Ended	12 Months Ended
		Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($) Countries Customers	Dec. 31, 2017 USD ($) Countries Customers	Dec. 31, 2016 USD ($)
Concentration Risk [Line Items]
Maximum Percentage Gross Trade Receivables From One Geographic Segment			10.00%	10.00%
Maximum Percentage Gross Trade Receivables From One Customer			10.00%	10.00%
NumberOfCountriesExceedReceivablesThreshold | Countries			1	1
NumberOfCustomersExceedReceivablesThreshold | Customers			0	0
Foreign Currency Exchange Rate, Remeasurement		50,000		10
Impairments and other charges		$ 312
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at Beginning of Period		725	$ 725	$ 175	$ 145
Provision (a)	[1]		57	566	50
Other (b)	[2]		(44)	(16)	(20)
Balance at End of Period			$ 738	$ 725	$ 175
UNITED STATES | Geographic Concentration Risk | Accounts Receivable
Concentration Risk [Line Items]
Concentration Risk, Percentage			43.00%	42.00%
VENEZUELA
Concentration Risk [Line Items]
Allowance for Doubtful Accounts Receivable, Write-offs		119
Write-off of promissory note in Venezuela		32
Inventory Write-down		48
Fixed asset write-offs in Venezuela		53
Other asset and liability write-offs in Venezuela		13
Accrued taxes portion of Venezuela investment write-down		$ 47

[1] Represents increases to allowance for bad debts charged to costs and expenses, net of recoveries.

[2] Includes write-offs, balance sheet reclassifications, and other activity.