Asset Impairments and Unusual Items - Components (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Asset Impairments and Unusual Items
(Gain) loss from divestitures			$ (40)		$ (96)	$ (38)
Asset impairments	$ 16	$ 8		$ 42	38	41
Other						(19)
(Gain) loss from divestitures, asset impairments and unusual items				$ 42	$ (58)	$ (16)

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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- References

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- Definition

Amount of gain (loss) on sale or disposal of assets, including but not limited to property plant and equipment, intangible assets and equity in securities of subsidiaries or equity method investee.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

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Amount of other expense that is infrequent in occurrence or unusual in nature.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 20
-Section 50
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- Definition

The aggregate amount of asset impairment charges, (gains) and losses related to the divestiture of businesses and unusual items incurred during an accounting period.

+ References

No definition available.

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