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v3.19.3.a.u2

Post-retirement benefits - Summary of geographical distribution of defined benefit obligations (Detail) | 12 Months Ended
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Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Disclosure of defined benefit plans [Line Items] |  |  |
Defined benefit obligation | 100.00% | 100.00% | 100.00%
Canada [Member] |  |  |
Disclosure of defined benefit plans [Line Items] |  |  |
Defined benefit obligation | 53.00% | 48.00% | 49.00%
UK [Member] |  |  |
Disclosure of defined benefit plans [Line Items] |  |  |
Defined benefit obligation | 28.00% | 28.00% | 27.00%
United States of America [Member] |  |  |
Disclosure of defined benefit plans [Line Items] |  |  |
Defined benefit obligation | 10.00% | 14.00% | 14.00%
Switzerland |  |  |
Disclosure of defined benefit plans [Line Items] |  |  |
Defined benefit obligation | 5.00% | 5.00% | 5.00%
Other countries [Member] |  |  |
Disclosure of defined benefit plans [Line Items] |  |  |
Defined benefit obligation | 4.00% | 5.00% | 5.00%
Pension benefits [member] |  |  |
Disclosure of defined benefit plans [Line Items] |  |  |
Defined benefit obligation | 100.00% |  |
Pension benefits [member] | Canada [Member] |  |  |
Disclosure of defined benefit plans [Line Items] |  |  |
Defined benefit obligation | 54.00% |  |
Pension benefits [member] | UK [Member] |  |  |
Disclosure of defined benefit plans [Line Items] |  |  |
Defined benefit obligation | 30.00% |  |
Pension benefits [member] | United States of America [Member] |  |  |
Disclosure of defined benefit plans [Line Items] |  |  |
Defined benefit obligation | 7.00% |  |
Pension benefits [member] | Switzerland |  |  |
Disclosure of defined benefit plans [Line Items] |  |  |
Defined benefit obligation | 5.00% |  |
Pension benefits [member] | Other countries [Member] |  |  |
Disclosure of defined benefit plans [Line Items] |  |  |
Defined benefit obligation | 4.00% |  |
Other Benefits [member] |  |  |
Disclosure of defined benefit plans [Line Items] |  |  |
Defined benefit obligation | 100.00% |  |
Other Benefits [member] | Canada [Member] |  |  |
Disclosure of defined benefit plans [Line Items] |  |  |
Defined benefit obligation | 44.00% |  |
Other Benefits [member] | UK [Member] |  |  |
Disclosure of defined benefit plans [Line Items] |  |  |
Defined benefit obligation | 2.00% |  |
Other Benefits [member] | United States of America [Member] |  |  |
Disclosure of defined benefit plans [Line Items] |  |  |
Defined benefit obligation | 51.00% |  |
Other Benefits [member] | Switzerland |  |  |
Disclosure of defined benefit plans [Line Items] |  |  |
Defined benefit obligation | 0.00% |  |
Other Benefits [member] | Other countries [Member] |  |  |
Disclosure of defined benefit plans [Line Items] |  |  |
Defined benefit obligation | 3.00% |  |

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- Definition Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table. + References No definition available. + Details
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- Definition Defined benefit obligation maturity percentage. + References No definition available. + Details
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- Details
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- Details
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- Details
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