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Restructuring - Schedule of Restructuring and Related Expense (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Restructuring Cost and Reserve [Line Items] |  |  |
Incurred restructuring cost |  |  | $ 497
2017 Plan |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |
Incurred restructuring cost | $ 451 | $ 485 |
Completed Plan Total | 1,433 |  |
Workforce reduction | 2017 Plan |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |
Incurred restructuring cost | 205 | 115 | 299
Completed Plan Total | 619 |  |
Technology rationalization | 2017 Plan |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |
Incurred restructuring cost | 39 | 47 | 33
Completed Plan Total | 119 |  |
Incurred contract termination costs | 0 | 5 | 1
Lease consolidation | 2017 Plan |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |
Incurred restructuring cost | 33 | 28 | 8
Completed Plan Total | 69 |  |
Incurred contract termination costs | 33 | 25 | 8
Asset impairments | 2017 Plan |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |
Incurred restructuring cost | 14 | 13 | 26
Completed Plan Total | 53 |  |
Other Restructuring | 2017 Plan |  |  |
Restructuring Cost and Reserve [Line Items] |  |  |
Incurred restructuring cost | 160 | 282 | 131
Completed Plan Total | 573 |  |
Incurred contract termination costs | $ 13 | $ 85 | $ 3

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- Definition Amount of costs incurred to date 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 50 -Paragraph 1 -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869 Reference 2: 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 3: 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 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(b)(1)) -URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747 + Details
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