Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Changes in accumulated other comprehensive income (loss), net of income taxes
Beginning of the period	$ 30,524
Other Comprehensive Income (Loss)	(879)	$ (1,192)	$ 1,052
End of the period	31,088	30,524
Accumulated Other Comprehensive Income (Loss):
Changes in accumulated other comprehensive income (loss), net of income taxes
Beginning of the period	(7,586)	(6,062)
Impact of adoption of new accounting standards		(332)
Other comprehensive income (loss) before reclassifications	(729)	(1,448)
(Income) loss amounts reclassified from accumulated other comprehensive income	(150)	256
Other Comprehensive Income (Loss)	(879)	(1,192)	1,052
End of the period	(8,465)	(7,586)	(6,062)
Cumulative Foreign Currency Translation Adjustments
Changes in accumulated other comprehensive income (loss), net of income taxes
Beginning of the period	(4,912)	(3,452)
Other comprehensive income (loss) before reclassifications	(12)	(1,488)
(Income) loss amounts reclassified from accumulated other comprehensive income		28
Other Comprehensive Income (Loss)	(12)	(1,460)
End of the period	(4,924)	(4,912)	(3,452)
Net Actuarial (Losses) and Prior Service (Costs) and Credits
Changes in accumulated other comprehensive income (loss), net of income taxes
Beginning of the period	(2,726)	(2,521)
Impact of adoption of new accounting standards		(337)
Other comprehensive income (loss) before reclassifications	(719)	(18)
(Income) loss amounts reclassified from accumulated other comprehensive income	(95)	150
Other Comprehensive Income (Loss)	(814)	132
End of the period	(3,540)	(2,726)	(2,521)
Cumulative Unrealized Gains (Losses) on Marketable Equity Securities
Changes in accumulated other comprehensive income (loss), net of income taxes
Beginning of the period		(5)
Impact of adoption of new accounting standards		5
End of the period			(5)
Cumulative Gains (Losses) on Derivative Instruments Designated as Cash Flow Hedges
Changes in accumulated other comprehensive income (loss), net of income taxes
Beginning of the period	52	(84)
Other comprehensive income (loss) before reclassifications	2	58
(Income) loss amounts reclassified from accumulated other comprehensive income	(55)	78
Other Comprehensive Income (Loss)	(53)	136
End of the period	$ (1)	$ 52	$ (84)

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Amount after tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption.

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Amount after tax, before reclassification adjustments of other comprehensive income (loss).

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Amount after tax of other comprehensive income (loss) attributable to parent entity.

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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