Long-Term Employee Benefit Liabilities - Future Benefit Payments (Detail) $ in Millions	Dec. 31, 2020 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Expected employer contributions - 2021	$ 24
2021	35
2022	37
2023	39
2024	43
2025	50
Thereafter	283
Total	487
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected employer contributions - 2021	13
2021	24
2022	25
2023	25
2024	26
2025	27
Thereafter	151
Total	278
Termination and Long Service Arrangements [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected employer contributions - 2021	10
2021	10
2022	11
2023	13
2024	15
2025	21
Thereafter	124
Total	194
Retirement Medical Benefits Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected employer contributions - 2021	1
2021	1
2022	1
2023	1
2024	2
2025	2
Thereafter	8
Total	$ 15

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Amount of contribution expected to be received by defined benefit plan from employer in next fiscal year following current fiscal year.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 55
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=118257860&loc=d3e4587-114921

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