Equity, Reclassification Out of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Loss [Line Items]
Other income, net										$ 104		$ 130		$ 112
Total before tax										3,486		4,232		3,207
Tax benefit										(702)		(879)		949
Net income		$ 1,330	$ 639	$ 648	$ 167	$ 1,022	$ 874	$ 875	$ 582	2,784		3,353		4,156
Revenues		$ 27,879	$ 27,249	$ 28,933	$ 24,263	$ 28,730	$ 30,849	$ 31,015	$ 26,439	108,324	[1]	117,033	[1]	93,980	[1]
Reclassification out of Accumulated Other Comprehensive Loss [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Loss [Line Items]
Net income										(8)		(32)		(12)
Net Gain (Loss) on Pension and Other Postretirement Benefits [Member] | Reclassification out of Accumulated Other Comprehensive Loss [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Loss [Line Items]
Total before tax										(14)		(41)		(18)
Tax benefit										4		9		6
Net income										(10)		(32)		(12)
Net Actuarial Loss [Member] | Reclassification out of Accumulated Other Comprehensive Loss [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Loss [Line Items]
Other income, net	[2]									(38)		(63)		(50)
Prior Service Credit [Member] | Reclassification out of Accumulated Other Comprehensive Loss [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Loss [Line Items]
Other income, net	[2]									28		29		36
Curtailment and Settlement [Member] | Reclassification out of Accumulated Other Comprehensive Loss [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Loss [Line Items]
Other income, net	[2]									(4)		(7)		(4)
Gains on Cash Flow Hedges [Member[ | Reclassification out of Accumulated Other Comprehensive Loss [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Loss [Line Items]
Net income										2
Gains on Cash Flow Hedges [Member[ | Reclassification out of Accumulated Other Comprehensive Loss [Member] | Commodity Contracts [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Loss [Line Items]
Revenues										$ 2
Gains on Cash Flow Hedges [Member[ | Reclassification out of Accumulated Other Comprehensive Loss [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Loss [Line Items]
Net income												0		0
Gains on Cash Flow Hedges [Member[ | Reclassification out of Accumulated Other Comprehensive Loss [Member] | Commodity Contracts [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Loss [Line Items]
Revenues												$ 0		$ 0

[1] Includes excise taxes on sales by certain of our international operations of $5,595 million, $5,626 million, and $5,573 million for the years ended December 31, 2019, 2018, and 2017.

[2] These accumulated other comprehensive loss components are included in the computation of net periodic benefit cost (credit), as discussed in Note 13.