Income Taxes - Reconciliation of Tax Contingencies (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Gross tax contingencies – beginning of period	$ 2,820	$ 3,923	$ 3,414
Gross increases to tax positions in prior periods	403	88	216
Gross decreases to tax positions in prior periods	(354)	(465)	(181)
Gross increases to current period tax positions	507	507	707
Settlements with tax authorities	(60)	(1,207)	(207)
Lapse of statute of limitations	(74)	(26)	(26)
Gross tax contingencies - end of period	3,242	$ 2,820	$ 3,923
Tax contingencies, that if fully recognized, would decrease our effective tax rate	$ 1,600

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

No definition available.

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- Definition

Amount of unrecognized tax benefits.

+ References

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Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities.

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Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations.

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The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate.

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