Financial Instruments (Effect of Derivative Instruments on Income and Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Derivatives in Net Investment Hedging Relationship:
Other income (expense), net	$ 6,858	$ 5,394	$ 7,389
Foreign exchange contracts
Derivatives not designated as hedging instruments	(902)
Revenues
Foreign exchange contracts
Total gains (losses)	177	455	(138)
Other income (expense), net
Foreign exchange contracts
Total gains (losses)	(33)	(145)	169
Foreign exchange contracts
Derivatives in Net Investment Hedging Relationship:
Total	(786)	155	494
Foreign exchange contracts \| Derivatives in Cash Flow Hedging Relationship:
Derivatives in Cash Flow Hedging Relationship
Amount included in the assessment of effectiveness	102	38	332
Amount excluded from the assessment of effectiveness	(37)	(14)	26
Foreign exchange contracts \| Derivatives in Cash Flow Hedging Relationship: \| Revenues
Foreign exchange contracts
Amount of gains (losses) reclassified from AOCI to income	144	367	(139)
Amount excluded from the assessment of effectiveness recognized in earnings based on an amortization approach	33	88	1
Foreign exchange contracts \| Derivatives in Cash Flow Hedging Relationship: \| Other income (expense), net
Foreign exchange contracts
Amount of gains (losses) reclassified from AOCI to income	0	0	0
Amount excluded from the assessment of effectiveness recognized in earnings based on an amortization approach	0	0	0
Foreign exchange contracts \| Derivatives in Net Investment Hedging Relationship:
Derivatives in Net Investment Hedging Relationship:
Amount included in the assessment of effectiveness	(851)	131	136
Foreign exchange contracts \| Derivatives in Net Investment Hedging Relationship: \| Revenues
Foreign exchange contracts
Amount excluded from the assessment of effectiveness	0	0	0
Foreign exchange contracts \| Derivatives in Net Investment Hedging Relationship: \| Other income (expense), net
Foreign exchange contracts
Amount excluded from the assessment of effectiveness	151	243	78
Foreign exchange contracts \| Fair value hedges \| Revenues
Foreign exchange contracts
Hedged items	0	0	0
Derivatives designated as hedging instruments	0	0	0
Amount excluded from the assessment of effectiveness	0	0	0
Foreign exchange contracts \| Fair value hedges \| Other income (expense), net
Foreign exchange contracts
Hedged items	18	(19)	(96)
Derivatives designated as hedging instruments	(18)	19	96
Amount excluded from the assessment of effectiveness	4	25	37
Fair Value of Derivatives Not Designated as Hedging Instruments \| Foreign exchange contracts \| Revenues
Foreign exchange contracts
Derivatives not designated as hedging instruments	0	0	0
Fair Value of Derivatives Not Designated as Hedging Instruments \| Foreign exchange contracts \| Other income (expense), net
Foreign exchange contracts
Derivatives not designated as hedging instruments	718	(413)	54
Fair Value of Derivatives Not Designated as Hedging Instruments \| Other contracts \| Revenues
Foreign exchange contracts
Derivatives not designated as hedging instruments	0	0	0
Fair Value of Derivatives Not Designated as Hedging Instruments \| Other contracts \| Other income (expense), net
Foreign exchange contracts
Derivatives not designated as hedging instruments	$ (906)	$ 0	$ 0

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