Income Taxes - Rollforward of Unrecognized Tax Benefits (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
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| Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] | |||
| Balance, beginning of year | $ 1,445 | $ 1,051 | $ 665 |
| Increases based on current year tax positions | 164 | 131 | 197 |
| Increases based on prior years' tax positions | 209 | 441 | 232 |
| Decreases based on prior years' tax positions | (205) | (54) | (39) |
| Decreases related to settlements | (367) | (125) | (3) |
| Exchange rate fluctuations | 5 | 1 | (1) |
| Balance, end of year | 1,251 | 1,445 | 1,051 |
| Related deferred income tax asset | 200 | 279 | 152 |
| Net unrecognized tax benefit | $ 1,051 | $ 1,166 | $ 899 |
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- Definition Assets related to unrecognized tax benefits. No definition available.
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- Definition Increase or (decrease) in unrecognized tax benefits due to exchange rate fluctuations. No definition available.
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- Definition 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. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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