Income Taxes - Reconciliation of Gross Unrecognized Tax Benefits (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
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| Income Tax Disclosure [Abstract] | |||
| Unrecognized tax benefits, beginning balance | $ 900 | $ 795 | $ 629 |
| Additions for tax positions of prior years | 31 | 99 | 82 |
| Reductions for tax positions of prior years | (8) | (27) | (15) |
| Additions based on tax positions related to current year | 60 | 47 | 102 |
| Lapse of statute of limitations | (3) | (4) | (3) |
| Settlements | (40) | (10) | |
| Unrecognized tax benefits, ending balance | $ 940 | $ 900 | $ 795 |
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- References 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 Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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