Receivables (Details) $ in Millions		12 Months Ended
		Dec. 31, 2020 USD ($) Countries Customers		Dec. 31, 2019 USD ($) Customers Countries		Dec. 31, 2018 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
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at Beginning of Period		$ 776	[1]	$ 738	[1]	$ 725
Provision (a)	[2]	58		50		57
Other (b)	[3]	(10)		(12)		(44)
Balance at End of Period (c)	[1]	$ 824		$ 776		$ 738
UNITED STATES | Geographic Concentration Risk | Accounts Receivable
Concentration Risk [Line Items]
Concentration Risk, Percentage		32.00%		36.00%

[1] The allowance for credit losses in all years is primarily comprised of a full reserve against accounts receivable with our primary customer in Venezuela.

[2] Represents increases to allowance for credit losses charged to costs and expenses, net of recoveries.

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