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Long-Term Employee Benefit Liabilities - Future Benefit Payments (Detail) $ in Millions | Dec. 31, 2017 USD ($)
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Defined Benefit Plan Disclosure [Line Items] |
Expected employer contributions - 2018 | $ 31
2018 | 35
2019 | 36
2020 | 40
2021 | 42
2022 | 46
Thereafter | 251
Total | 450
Pension Plan, Defined Benefit [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Expected employer contributions - 2018 | 19
2018 | 23
2019 | 23
2020 | 24
2021 | 25
2022 | 26
Thereafter | 143
Total | 264
Termination and Long Service Arrangements [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Expected employer contributions - 2018 | 10
2018 | 10
2019 | 11
2020 | 14
2021 | 15
2022 | 18
Thereafter | 99
Total | 167
Retirement Medical Benefits Plans [Member] |
Defined Benefit Plan Disclosure [Line Items] |
Expected employer contributions - 2018 | 2
2018 | 2
2019 | 2
2020 | 2
2021 | 2
2022 | 2
Thereafter | 9
Total | $ 19

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