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Accounting Standards - Additional Information (Detail) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2017 | Dec. 31, 2016
New Accounting Pronouncement, Early Adoption [Line Items] |  |
Sales | $ 38,946 | $ 36,445
Cost of goods sold | 33,258 | $ 31,123
Accounting Standards Update 2014-09 [Member] | Change In Accounting For Tooling And Pre-Production Engineering Activities [Member] |  |
New Accounting Pronouncement, Early Adoption [Line Items] |  |
Sales | (2,400) |
Cost of goods sold | $ (2,400) |

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- Definition Total costs related to goods produced and sold during the reporting period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.2(a)) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688 + Details
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