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Restructuring - Schedule of Restructuring and Related Expenses (Details) - 2017 Plan $ in Millions | 3 Months Ended | 27 Months Ended
--- | --- | ---
Mar. 31, 2019 USD ($) | Mar. 31, 2019 USD ($)
Restructuring Cost and Reserve [Line Items] |  |
Costs incurred | $ 91 | $ 1,073
Estimated Remaining Costs | 152 | 152
Expected total cost | 1,225 | 1,225
Workforce reduction |  |
Restructuring Cost and Reserve [Line Items] |  |
Costs incurred | 24 | 438
Estimated Remaining Costs | 12 | 12
Expected total cost | 450 | 450
Technology rationalization |  |
Restructuring Cost and Reserve [Line Items] |  |
Costs incurred | 11 | 91
Estimated Remaining Costs | 39 | 39
Expected total cost | 130 | 130
Contract termination costs incurred | 1 | 7
Expected contract termination cost remaining | 15 | 15
Lease consolidation |  |
Restructuring Cost and Reserve [Line Items] |  |
Costs incurred | 9 | 45
Estimated Remaining Costs | 20 | 20
Expected total cost | 65 | 65
Contract termination costs incurred | 9 | 42
Expected contract termination cost remaining | 80 | 80
Asset impairments |  |
Restructuring Cost and Reserve [Line Items] |  |
Costs incurred | 0 | 39
Estimated Remaining Costs | 11 | 11
Expected total cost | 50 | 50
Other costs associated with restructuring and separation |  |
Restructuring Cost and Reserve [Line Items] |  |
Costs incurred | 47 | 460
Estimated Remaining Costs | 70 | 70
Expected total cost | 530 | 530
Contract termination costs incurred | 2 | 90
Expected contract termination cost remaining | $ 95 | $ 95

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