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Restructuring - Narrative (Details) - 2017 Plan $ in Millions | 3 Months Ended | 9 Months Ended | 33 Months Ended
--- | --- | --- | ---
Jun. 30, 2019 USD ($) | Sep. 30, 2019 USD ($) job_elimination | Sep. 30, 2019 USD ($) job_elimination
Restructuring Cost and Reserve [Line Items] |  |  |
Restructuring charges | $ 125 | $ 260 | $ 1,263
Expected total cost |  | 1,350 | $ 1,350
Number of positions eliminated to date | job_elimination |  |  | 5,353
Workforce reduction |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |
Expected total cost |  | 550 | $ 550
Technology rationalization |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |
Expected total cost |  | 125 | 125
Lease consolidation |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |
Expected total cost |  | 80 | 80
Asset impairments |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |
Expected total cost |  | 50 | 50
Other Restructuring |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |
Expected total cost |  | $ 545 | $ 545
Minimum |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |
Expected number of positions eliminated | job_elimination |  | 5,400 |
Maximum |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |
Expected number of positions eliminated | job_elimination |  | 5,600 |

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