Income Taxes - Reconciliation of unrecognized tax benefits (UTB) (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
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| Federal, State and Foreign Tax | |||
| Gross UTB Balance at January 1 | $ 1,167 | $ 647 | $ 530 |
| Additions based on tax positions related to the current year | 74 | 76 | 129 |
| Additions for tax positions of prior years | 106 | 132 | 146 |
| Additions related to recent acquisitions | 396 | ||
| Reductions for tax positions of prior years | (173) | (56) | (123) |
| Settlements | (8) | (4) | (17) |
| Reductions due to lapse of applicable statute of limitations | (53) | (24) | (18) |
| Gross UTB Balance at December 31 | 1,113 | 1,167 | 647 |
| Net UTB that would impact the effective tax rate at December 31 | $ 1,145 | $ 1,178 | $ 655 |
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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 acquisitions. No definition available.
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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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