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Restructuring - Narrative (Details) - USD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2021
Restructuring Cost and Reserve [Line Items] |  |  |  |
Restructuring costs | $ 883 | $ 927 | $ 658 |
Expected costs | $ 3,000 |  |  |
Percentage estimate of cumulative pretax costs that will result in cash outlays (primarily from employee separation expense) (as percent) | 70.00% |  |  |
Percentage estimate of cumulative pretax costs that will be non-cash (primarily from accelerated depreciation of facilities) (as percent) | 30.00% |  |  |
Restructuring costs, cost incurred to date | $ 1,800 |  |  |
Forecast |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |
Expected costs |  |  |  | $ 700

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- Definition Amount of costs incurred to date for the specified restructuring cost. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 420 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 420 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 420 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SAB Topic 5.P.4(d)) -URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 420 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SAB Topic 5.P.4(b)(1)) -URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747 + Details
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