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Operating segments - additional information - Summary of non-current assets other than excluded items (Parenthetical) (Detail) - USD ($) $ in Millions | Dec. 31, 2018 | Dec. 31, 2017
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Quasi equity loans [member] |  |
Disclosure Of Geographical Areas [Line Items] |  |
Quasi equity loans to equity accounted units | $ 129 | $ 159
Non-quasi equity loan [member] |  |
Disclosure Of Geographical Areas [Line Items] |  |
Investments in equity accounted units | 38 | 39
Non-current assets [member] |  |
Disclosure Of Geographical Areas [Line Items] |  |
Investments in equity accounted units | 4,170 | $ 4,327
France [member] |  |
Disclosure Of Geographical Areas [Line Items] |  |
Change in non-current assets other than excluded items | $ 182 |

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- Definition The amount of investments accounted for using equity method, excluding quasi equity loans (quasi-equity loans are long term loans to equity accounted units that in substance form part of the net investment and are reported in the line “Investments in equity accounted units” on the face of the balance sheet. + References No definition available. + Details
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- Definition Quasi equity loans are long term loans to equity accounted units that in substance form part of the net investment and are reported in the line “Investments in equity accounted units” on the face of the balance sheet. + References No definition available. + Details
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