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Restructuring and Other Charges - Activity and Reserve Balances for Restructuring Charges (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | ---
Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017 | Dec. 31, 2017
Restructuring Reserve [Roll Forward] |  |  |  |  |
Restructuring reserve beginning balance |  |  | $ 58 | $ 59 | $ 59
Cash payments |  |  | (38) |  | (65)
Restructuring charges |  |  | 21 |  | 65
Other |  |  | 0 |  | (1)
Restructuring reserve ending balance | $ 41 |  | 41 |  | 58
Restructuring and other charges | (2) | $ 19 | 20 | 118 |
Layoff costs |  |  |  |  |
Restructuring Reserve [Roll Forward] |  |  |  |  |
Restructuring reserve beginning balance |  |  | 56 | 50 | 50
Cash payments |  |  | (37) |  | (59)
Restructuring charges |  |  | 8 |  | 64
Other |  |  | 0 |  | 1
Restructuring reserve ending balance | 27 |  | 27 |  | 56
Other exit costs |  |  |  |  |
Restructuring Reserve [Roll Forward] |  |  |  |  |
Restructuring reserve beginning balance |  |  | 2 | $ 9 | 9
Cash payments |  |  | (1) |  | (6)
Restructuring charges |  |  | 13 |  | 1
Other |  |  | 0 |  | (2)
Restructuring reserve ending balance | $ 14 |  | 14 |  | 2
Postretirement benefits |  |  |  |  |
Restructuring Reserve [Roll Forward] |  |  |  |  |
Restructuring and other charges |  |  | 28 |  |
Pension costs |  |  |  |  |
Restructuring Reserve [Roll Forward] |  |  |  |  |
Restructuring and other charges |  |  | $ 18 |  |
Stock awards reversal |  |  |  |  |
Restructuring Reserve [Roll Forward] |  |  |  |  |
Restructuring and other charges |  |  |  |  | $ 13

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- Definition Restructuring reserve period expenses. + References No definition available. + Details
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- Definition Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation. + 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)(2) -URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 17 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3367-108585 + Details
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- Definition Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 420 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 5.P.3) -URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140864-122747 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 420 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 420 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SAB Topic 5.P.4(b)) -URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747 + Details
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- Definition Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 420 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b)(2) -URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 420 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SAB TOPIC 5.P.4(b)) -URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747 + Details
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- Definition Amount of expense (reversal of expense) which increases (decreases) the restructuring reserve from an adjustment to a previously accrued restructuring liability. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 420 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 420 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SAB TOPIC 5.P.4(b)(2)) -URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747 + Details
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