Commitments and Contingent Liabilities (Litigation Settlements - Asbestos Matters and Other Disclosure) (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2020
Other Reserves		$ 190
Asbestos Issue
Loss Contingency, Pending Claims, Number		840
Other Reserves		$ 162
Increase to asbestos reserve	$ 10
Pittsburgh Corning Corporation
Ownership interest		50.00%

Difference between the 2nd and 3rd amended PC plan of re-organization in cash to be contributed to the Trust by PPG which has been established as a reserve for asbestos-related claims that will not be channeled to the Trust.

No definition available.

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- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

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- Definition

The increase (decrease) during the reporting period in asbestos and environmental claims reserve, before estimated recoveries from reinsurers.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 40
-Section 50
-Paragraph 3
-Subparagraph (b),(c)
-URI http://asc.fasb.org/extlink&oid=116884095&loc=d3e14764-158437

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- Definition

Number of pending claims pertaining to a loss contingency.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14435-108349

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