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v3.19.1

Share-based compensation - Range of exercise prices in SARs and TSARs (Details) | Dec. 31, 2018 USD ($) year shares | Dec. 31, 2017 USD ($) shares | Dec. 31, 2016 USD ($) shares
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SARs |  |  |
Disclosure of terms and conditions of share-based payment arrangement [line items] |  |  |
Weighted average remaining contractual life (years) | year | 3.84 |  |
Number of units outstanding | shares | 896,883 | 1,450,077 | 1,511,485
Weighted average exercise price of units outstanding (in usd per unit) | $ 51.27 | $ 45.11 | $ 42.68
Number of units exercisable | shares | 535,878 |  |
Weighted average exercise price of units exercisable (in usd per unit) | $ 54.04 |  |
SARs | $25.97 to $35.51 |  |  |
Disclosure of terms and conditions of share-based payment arrangement [line items] |  |  |
Weighted average remaining contractual life (years) | year | 3.96 |  |
Number of units outstanding | shares | 221,309 |  |
Weighted average exercise price of units outstanding (in usd per unit) | $ 34.40 |  |
Number of units exercisable | shares | 105,955 |  |
Weighted average exercise price of units exercisable (in usd per unit) | $ 34.19 |  |
SARs | $25.97 to $35.51 | Minimum |  |  |
Disclosure of terms and conditions of share-based payment arrangement [line items] |  |  |
Weighted average exercise price of units outstanding (in usd per unit) | 25.97 |  |
SARs | $25.97 to $35.51 | Maximum |  |  |
Disclosure of terms and conditions of share-based payment arrangement [line items] |  |  |
Weighted average exercise price of units outstanding (in usd per unit) | $ 35.51 |  |
SARs | $38.24 to $50.17 |  |  |
Disclosure of terms and conditions of share-based payment arrangement [line items] |  |  |
Weighted average remaining contractual life (years) | year | 3.95 |  |
Number of units outstanding | shares | 205,951 |  |
Weighted average exercise price of units outstanding (in usd per unit) | $ 46.52 |  |
Number of units exercisable | shares | 99,000 |  |
Weighted average exercise price of units exercisable (in usd per unit) | $ 42.59 |  |
SARs | $38.24 to $50.17 | Minimum |  |  |
Disclosure of terms and conditions of share-based payment arrangement [line items] |  |  |
Weighted average exercise price of units outstanding (in usd per unit) | 38.24 |  |
SARs | $38.24 to $50.17 | Maximum |  |  |
Disclosure of terms and conditions of share-based payment arrangement [line items] |  |  |
Weighted average exercise price of units outstanding (in usd per unit) | $ 50.17 |  |
SARs | $54.65 to $78.59 |  |  |
Disclosure of terms and conditions of share-based payment arrangement [line items] |  |  |
Weighted average remaining contractual life (years) | year | 3.73 |  |
Number of units outstanding | shares | 469,623 |  |
Weighted average exercise price of units outstanding (in usd per unit) | $ 61.31 |  |
Number of units exercisable | shares | 330,923 |  |
Weighted average exercise price of units exercisable (in usd per unit) | $ 63.83 |  |
SARs | $54.65 to $78.59 | Minimum |  |  |
Disclosure of terms and conditions of share-based payment arrangement [line items] |  |  |
Weighted average exercise price of units outstanding (in usd per unit) | 54.65 |  |
SARs | $54.65 to $78.59 | Maximum |  |  |
Disclosure of terms and conditions of share-based payment arrangement [line items] |  |  |
Weighted average exercise price of units outstanding (in usd per unit) | $ 78.59 |  |
TSARs |  |  |
Disclosure of terms and conditions of share-based payment arrangement [line items] |  |  |
Weighted average remaining contractual life (years) | year | 4.22 |  |
Number of units outstanding | shares | 1,447,301 | 2,043,495 | 2,416,111
Weighted average exercise price of units outstanding (in usd per unit) | $ 51.24 | $ 46.62 | $ 42.10
Number of units exercisable | shares | 709,272 |  |
Weighted average exercise price of units exercisable (in usd per unit) | $ 54.05 |  |
TSARs | $25.97 to $35.51 |  |  |
Disclosure of terms and conditions of share-based payment arrangement [line items] |  |  |
Weighted average remaining contractual life (years) | year | 3.99 |  |
Number of units outstanding | shares | 347,839 |  |
Weighted average exercise price of units outstanding (in usd per unit) | $ 34.47 |  |
Number of units exercisable | shares | 161,261 |  |
Weighted average exercise price of units exercisable (in usd per unit) | $ 34.32 |  |
TSARs | $25.97 to $35.51 | Minimum |  |  |
Disclosure of terms and conditions of share-based payment arrangement [line items] |  |  |
Weighted average exercise price of units outstanding (in usd per unit) | 25.97 |  |
TSARs | $25.97 to $35.51 | Maximum |  |  |
Disclosure of terms and conditions of share-based payment arrangement [line items] |  |  |
Weighted average exercise price of units outstanding (in usd per unit) | $ 35.51 |  |
TSARs | $38.24 to $50.17 |  |  |
Disclosure of terms and conditions of share-based payment arrangement [line items] |  |  |
Weighted average remaining contractual life (years) | year | 4.41 |  |
Number of units outstanding | shares | 386,253 |  |
Weighted average exercise price of units outstanding (in usd per unit) | $ 47.88 |  |
Number of units exercisable | shares | 161,902 |  |
Weighted average exercise price of units exercisable (in usd per unit) | $ 44.72 |  |
TSARs | $38.24 to $50.17 | Minimum |  |  |
Disclosure of terms and conditions of share-based payment arrangement [line items] |  |  |
Weighted average exercise price of units outstanding (in usd per unit) | 38.24 |  |
TSARs | $38.24 to $50.17 | Maximum |  |  |
Disclosure of terms and conditions of share-based payment arrangement [line items] |  |  |
Weighted average exercise price of units outstanding (in usd per unit) | $ 50.17 |  |
TSARs | $54.65 to $78.59 |  |  |
Disclosure of terms and conditions of share-based payment arrangement [line items] |  |  |
Weighted average remaining contractual life (years) | year | 4.23 |  |
Number of units outstanding | shares | 713,209 |  |
Weighted average exercise price of units outstanding (in usd per unit) | $ 61.24 |  |
Number of units exercisable | shares | 386,109 |  |
Weighted average exercise price of units exercisable (in usd per unit) | $ 66.20 |  |
TSARs | $54.65 to $78.59 | Minimum |  |  |
Disclosure of terms and conditions of share-based payment arrangement [line items] |  |  |
Weighted average exercise price of units outstanding (in usd per unit) | 54.65 |  |
TSARs | $54.65 to $78.59 | Maximum |  |  |
Disclosure of terms and conditions of share-based payment arrangement [line items] |  |  |
Weighted average exercise price of units outstanding (in usd per unit) | $ 78.59 |  |

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