Income Taxes - Uncertain Tax Positions (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
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| Unrecognized Tax Benefits [Roll Forward] | |||
| Balance at beginning of period | $ 775 | $ 1,341 | $ 1,557 |
| Additions to current year tax positions | 435 | 18 | 292 |
| Additions to prior years' tax positions | 26 | 13 | 264 |
| Reductions to prior years' tax positions | (132) | (501) | (244) |
| Reductions in tax positions due to lapse of statutory limitations | (3) | (8) | (38) |
| Settlements | (10) | (93) | (450) |
| Other | (5) | 5 | (40) |
| Balance at end of period | 1,086 | 775 | $ 1,341 |
| Unrecognized tax benefit that would favorably affect effective tax rate | 851 | 539 | |
| Income tax related interest and penalties accrual | $ 92 | $ 117 | |
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- Definition This element represents a sum total of additions or reductions to reserves not separately reflected in the tabular roll for the period. 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 accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the 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 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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- 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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