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Restructuring - Schedule of Restructuring and Related Expenses (Details) - 2017 Plan $ in Millions | 3 Months Ended | 6 Months Ended | 18 Months Ended
--- | --- | --- | ---
Jun. 30, 2018 USD ($) | Jun. 30, 2018 USD ($) | Jun. 30, 2018 USD ($)
Restructuring Cost and Reserve [Line Items] |  |  |
Costs incurred | $ 195 | $ 269 | $ 766
Estimated Remaining Costs | 259 | 259 | 259
Expected total cost | 1,025 | 1,025 | 1,025
Workforce reduction |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |
Costs incurred | 33 | 66 | 365
Estimated Remaining Costs | 55 | 55 | 55
Expected total cost | 420 | 420 | 420
Technology rationalization |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |
Costs incurred | 8 | 18 | 51
Estimated Remaining Costs | 79 | 79 | 79
Expected total cost | 130 | 130 | 130
Contract termination costs incurred | 0 | 1 | 2
Expected contract termination cost remaining | 15 | 15 | 15
Lease consolidation |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |
Costs incurred | 10 | 13 | 21
Estimated Remaining Costs | 39 | 39 | 39
Expected total cost | 60 | 60 | 60
Contract termination costs incurred | 10 | 12 | 20
Expected contract termination cost remaining | 80 | 80 | 80
Asset impairments |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |
Costs incurred | 8 | 9 | 35
Estimated Remaining Costs | 5 | 5 | 5
Expected total cost | 40 | 40 | 40
Other costs associated with restructuring and separation |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |
Costs incurred | 136 | 163 | 294
Estimated Remaining Costs | 81 | 81 | 81
Expected total cost | 375 | 375 | 375
Contract termination costs incurred | 75 | 79 | 82
Expected contract termination cost remaining | $ 82 | $ 82 | $ 82

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- Definition Amount expected to be recognized in earnings 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 S99 -Paragraph 2 -Subparagraph (SAB Topic 5.P.4(b)(1)) -URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747 Reference 2: 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 3: 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 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(d)) -URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747 + Details
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