Analysis of goodwill is as follows:
| December 31, | ||||||||||||
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Variation of the period |
2017 | 2016 | 2015 | |||||||||
| (In millions of US$) | ||||||||||||
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Balance at beginning of period |
1,223.3 | 1,228.7 | 2,041.7 | |||||||||
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Additions |
— | — | 1.9 | |||||||||
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Impairment |
— | — | (803.8 | ) | ||||||||
|
Change in exchange rates |
10.7 | (5.4 | ) | (11.1 | ) | |||||||
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Balance at end of period |
1,234.0 | 1,223.3 | 1,228.7 | |||||||||
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