Derivative Instruments and Hedging Activities (Pre-Tax Gains (Losses) On Derivatives Designated As Hedging Instruments) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Derivative [Line Items]
Interest expense									$ 339	$ 402	$ 364
Revenues	$ 17,978	$ 15,126	$ 16,281	$ 14,970	$ 16,329	$ 16,726	$ 16,297	$ 15,304	64,355	64,656	64,341
Cost of products sold									59,902	60,509	60,160
Sales [Member]
Derivative [Line Items]
Total amount recognized in earnings										(44)	36
Designated As Hedging Instrument [Member]
Derivative [Line Items]
Total amount recognized in earnings									(45)	(100)	(76)
Designated As Hedging Instrument [Member] | Interest Expense [Member]
Derivative [Line Items]
Interest contracts effective amount recognized in earnings									(2)	1	1
Total amount recognized in earnings									(2)	1	1
Designated As Hedging Instrument [Member] | Cost Of Products Sold [Member]
Derivative [Line Items]
Commodity Contracts effective amount recognized in earnings									27	(11)	(113)
Total amount recognized in earnings									27	(11)	(113)
Designated As Hedging Instrument [Member] | Sales [Member]
Derivative [Line Items]
Interest contracts effective amount recognized in earnings									(75)
Commodity Contracts effective amount recognized in earnings									7	(44)	36
Total amount recognized in earnings									(68)
Designated As Hedging Instrument [Member] | Other Nonoperating Income (Expense)
Derivative [Line Items]
Interest contracts effective amount recognized in earnings									0	(46)
Commodity Contracts effective amount recognized in earnings									(2)
Total amount recognized in earnings									$ (2)	$ (46)	$ 0