Financial Instruments and Risk Management (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Number of days from period end	2 days
Foreign Currency Derivatives [Abstract]
Maximum term of currency derivative instruments (in years)	1 year
Long-term Debt, Percentage Bearing Fixed Interest, Amount	$ 9,800	$ 10,300
Estimate of Fair Value, Fair Value Disclosure
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	11,556	11,961
Estimate of Fair Value, Fair Value Disclosure | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	10,856	11,093
Estimate of Fair Value, Fair Value Disclosure | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	700	868
Estimate of Fair Value, Fair Value Disclosure | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	0	0
Carrying (Reported) Amount, Fair Value Disclosure
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt, Long-term and Short-term, Combined Amount	9,827	10,327
Foreign Exchange Contract [Member] | Other current assets | Level 2
Interest Rate Derivatives [Abstract]
Derivative, Notional Amount	817	513
Foreign Exchange Contract [Member] | Other assets | Level 2
Interest Rate Derivatives [Abstract]
Derivative, Notional Amount	$ 100	$ 100