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Restructuring - Charges Activities by Type of Cost (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2021 | Sep. 30, 2020 | Sep. 30, 2021 | Sep. 30, 2020
Restructuring Cost and Reserve [Line Items] |  |  |  |
Total pretax restructuring costs | $ 168 | $ 185 | $ 630 | $ 500
Separation Costs |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |
Total pretax restructuring costs | 17 | 61 | 310 | 143
Accelerated Depreciation |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |
Total pretax restructuring costs | 22 | 66 | 60 | 192
Other |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |
Total pretax restructuring costs | 129 | 58 | 260 | 165
Cost of sales |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |
Total pretax restructuring costs | 48 | 38 | 113 | 131
Cost of sales | Separation Costs |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |
Total pretax restructuring costs | 0 | 0 | 0 | 0
Cost of sales | Accelerated Depreciation |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |
Total pretax restructuring costs | 11 | 33 | 32 | 89
Cost of sales | Other |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |
Total pretax restructuring costs | 37 | 5 | 81 | 42
Selling, general and administrative |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |
Total pretax restructuring costs | 5 | 15 | 9 | 37
Selling, general and administrative | Separation Costs |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |
Total pretax restructuring costs | 0 | 0 | 0 | 0
Selling, general and administrative | Accelerated Depreciation |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |
Total pretax restructuring costs | 4 | 15 | 8 | 37
Selling, general and administrative | Other |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |
Total pretax restructuring costs | 1 | 0 | 1 | 0
Research and development |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |
Total pretax restructuring costs | 8 | 19 | 21 | 67
Research and development | Separation Costs |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |
Total pretax restructuring costs | 0 | 0 | 0 | 0
Research and development | Accelerated Depreciation |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |
Total pretax restructuring costs | 7 | 18 | 20 | 66
Research and development | Other |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |
Total pretax restructuring costs | 1 | 1 | 1 | 1
Restructuring costs |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |
Total pretax restructuring costs | 107 | 113 | 487 | 265
Restructuring costs | Separation Costs |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |
Total pretax restructuring costs | 17 | 61 | 310 | 143
Restructuring costs | Accelerated Depreciation |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |
Total pretax restructuring costs | 0 | 0 | 0 | 0
Restructuring costs | Other |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |
Total pretax restructuring costs | $ 90 | $ 52 | $ 177 | $ 122

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