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Restructuring - Schedule of Restructuring and Related Expenses (Details) - 2017 Plan $ in Millions | 3 Months Ended | 9 Months Ended | 33 Months Ended
--- | --- | --- | ---
Sep. 30, 2019 USD ($) | Jun. 30, 2019 USD ($) | Sep. 30, 2019 USD ($) | Sep. 30, 2019 USD ($) job_elimination
Restructuring Cost and Reserve [Line Items] |  |  |  |
Costs incurred | $ 63 |  | $ 281 |
Expensed |  | $ 125 | 260 | $ 1,263
Restructuring and Related Cost, Number of Positions Eliminated | job_elimination |  |  |  | 5,353
Estimated Remaining Costs | 87 |  | 87 | $ 87
Expected total cost | 1,350 |  | 1,350 | 1,350
Expected non-cash expense | 100 |  | 100 | 100
Workforce reduction |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |
Costs incurred | 9 |  | 111 | 525
Estimated Remaining Costs | 25 |  | 25 | 25
Expected total cost | 550 |  | 550 | 550
Technology rationalization |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |
Costs incurred | 14 |  | 29 | 109
Estimated Remaining Costs | 16 |  | 16 | 16
Expected total cost | 125 |  | 125 | 125
Contract termination costs incurred | 9 |  | 12 | 18
Expected contract termination cost remaining | 20 |  | 20 | 20
Lease consolidation |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |
Costs incurred | 3 |  | 17 | 53
Estimated Remaining Costs | 27 |  | 27 | 27
Expected total cost | 80 |  | 80 | 80
Contract termination costs incurred | 2 |  | 15 | 48
Expected contract termination cost remaining | 80 |  | 80 | 80
Asset impairments |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |
Costs incurred | 5 |  | 7 | 46
Estimated Remaining Costs | 4 |  | 4 | 4
Expected total cost | 50 |  | 50 | 50
Other costs associated with restructuring and separation |  |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |  |
Costs incurred | 32 |  | 117 | 530
Estimated Remaining Costs | 15 |  | 15 | 15
Expected total cost | 545 |  | 545 | 545
Contract termination costs incurred | 18 |  | 21 | 109
Expected contract termination cost remaining | $ 116 |  | $ 116 | $ 116

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