XML 61 R40.htm IDEA: XBRL DOCUMENT
v3.20.4

BENEFIT PLANS: (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2020
Post retirement defined benefit plans and defined contribution plan |
Components of net periodic benefit costs |
Schedule of the components of net periodic benefit costs | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
(in millions) |  | 2020 |  | 2019 |  | 2018
Service cost | ​ | $ | 1.4 | ​ | $ | 1.1 | ​ | $ | 1.0
Interest cost | ​ |  | 1.7 | ​ |  | 1.8 | ​ |  | 1.6
Expected return on plan assets | ​ |  | (2.9) | ​ |  | (3.5) | ​ |  | (3.4)
Amortization of net actuarial loss | ​ | ​ | 0.1 | ​ | ​ | — | ​ | ​ | —
Amortization of prior service cost / (credit) | ​ |  | 0.2 | ​ |  | 0.2 | ​ |  | 0.2
Settlement / Curtailment | ​ | ​ | (0.4) | ​ | ​ | — | ​ | ​ | (0.2)
Amortization of net loss/(gain) | ​ |  | 0.2 | ​ |  | 0.3 | ​ |  | 0.2
Net periodic benefit cost | ​ | $ | 0.3 | ​ | $ | (0.1) | ​ | $ | (0.6)
Schedule of changes in the benefit obligation and plan assets, the funded status of the plans and the amount recognized in balance sheet and accumulated other comprehensive income | ​
​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | As of December 31,
(in millions) |  | 2020 |  | 2019
Change in benefit obligation: | ​ | ​ | ​ | ​ | ​ | ​
Projected benefit obligation at beginning of year | ​ | $ | 33.7 | ​ | $ | 27.4
Service cost | ​ |  | 1.4 | ​ |  | 1.1
Interest cost | ​ |  | 1.7 | ​ |  | 1.8
Settlement | ​ |  | — | ​ |  | —
Benefits paid | ​ |  | (1.9) | ​ |  | (1.8)
Actuarial (gain)/loss | ​ |  | (4.2) | ​ |  | 3.6
Actuarial gain assumption changes | ​ |  | 0.8 | ​ |  | 0.9
Inflation adjustment | ​ |  | (1.6) | ​ |  | 0.7
Projected benefit obligation at end of year | ​ | $ | 29.9 | ​ | $ | 33.7
Change in plan assets: | ​ | ​ | ​ | ​ | ​ | ​
Fair value of plan assets at beginning of year | ​ | $ | 51.6 | ​ | $ | 46.7
Actual return on plan assets | ​ |  | 6.5 | ​ |  | 4.8
Employer contributions | ​ |  | (0.6) | ​ |  | (0.6)
Benefits paid | ​ |  | (0.9) | ​ |  | (0.9)
Currency exchange rate adjustment | ​ |  | (2.2) | ​ |  | 1.6
Fair value of plan assets at end of year | ​ | $ | 54.4 | ​ | $ | 51.6
Funded status at end of year: | ​ | $ | 24.5 | ​ | $ | 17.9
ASC-715 amounts recognized in statement of financial position consists of: | ​ | ​ | ​ | ​ | ​ | ​
Non-current assets | ​ | $ | 24.5 | ​ | $ | 17.9
Total | ​ | $ | 24.5 | ​ | $ | 17.9
ASC-715 amounts recognized in accumulated other comprehensive income (net of income taxes of $(2.3) million and $(5.4) million in 2020 and 2019, respectively) consists of: | ​ | ​ | ​ | ​ | ​ | ​
Net loss (gain) | ​ | $ | 3.0 | ​ | $ | 7.6
Prior service cost | ​ |  | 1.2 | ​ |  | 1.4
Total | ​ | $ | 4.2 | ​ | $ | 9.0
Schedule of changes in accumulated other comprehensive income | ​
​ | ​ | ​ | ​ | ​ | ​ | ​
(in millions) |  | 2020 |  | 2019
Reconciliation of accumulated other comprehensive income: | ​ | ​ | ​ | ​ | ​ | ​
Accumulated other comprehensive income at beginning of plan year | ​ | $ | 9.0 | ​ | $ | 7.2
Net loss/(gain) amortized during the year | ​ |  | (4.1) | ​ |  | 1.9
Net loss/(gain) occurring during the year | ​ |  | (0.3) | ​ |  | (0.2)
Prior service cost (credit) | ​ | ​ | — | ​ | ​ | —
Currency exchange rate adjustment | ​ |  | (0.4) | ​ |  | 0.1
Net adjustment to accumulated other comprehensive income (net of income taxes of $3.1 million and $(2.2) million in 2020 and 2019, respectively) | ​ |  | (4.8) | ​ |  | 1.8
Accumulated other comprehensive income at end of plan year | ​ | $ | 4.2 | ​ | $ | 9.0
Summary of the amounts in accumulated other comprehensive income amortized and recognized as a component of net periodic benefit cost, net of tax | ​
​ | ​ | ​ | ​ | ​ | ​ | ​
(in millions) |  | 2020 |  | 2019
Net loss / (gain) | ​ | $ | (4.1) | ​ | $ | 1.8
Amortization of net (loss) gain | ​ |  | (0.3) | ​ |  | (0.2)
Amortization of prior services cost (credit) | ​ | ​ | — | ​ | ​ | —
Total amortization expenses | ​ | $ | (4.4) | ​ | $ | 1.6
Schedule of assumptions used to determine the pension obligations and other post-retirement benefits | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Expatriate Plan |  | 2020 |  | 2019 |  | 2018 |
Discount rate |  | 1.90 | % | 2.85 | % | 3.90 | %
Expected long-term rate of return on plan asset |  | 3.50 | % | 4.00 | % | 4.00 | %
Rate of increase in future compensation level |  | N/A | ​ | N/A | ​ | N/A | ​
​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Mexican Plan(*) |  | 2020 |  | 2019 |  | 2018 |
Discount rate |  | 7.43 | % | 7.15 | % | 8.45 | %
Expected long-term rate of return on plan asset |  | 7.43 | % | 7.15 | % | 8.45 | %
Rate of increase in future compensation level |  | 4.50 | % | 4.50 | % | 4.50 | %
(*)These rates are based on Mexican pesos as pension obligations are denominated in this currency.
Scheduled maturities of the benefits expected to be paid in each of the next five years, and thereafter | ​
​ | ​ | ​ | ​
​ |  | Expected
Years | ​ | Benefit Payments
​ | ​ | (in millions)
2021 | ​ | $ | 3.1
2022 | ​ |  | 1.7
2023 | ​ |  | 1.8
2024 | ​ |  | 2.0
2025 | ​ |  | 1.8
2026 to 2028 | ​ |  | 12.5
Total | ​ | $ | 22.9
​
Post-retirement Health care plans |
Components of net periodic benefit costs |
Schedule of the components of net periodic benefit costs | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
(in millions) |  | 2020 |  | 2019 |  | 2018
Interest cost | ​ | $ | 1.3 | ​ | $ | 0.9 | ​ | $ | 0.9
Amortization of prior service cost/ (credit) | ​ |  | — | ​ |  | (0.2) | ​ |  | (0.2)
Net periodic benefit cost | ​ | $ | 1.3 | ​ | $ | 0.7 | ​ | $ | 0.7
​
Schedule of changes in the benefit obligation and plan assets, the funded status of the plans and the amount recognized in balance sheet and accumulated other comprehensive income | ​
​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | As of December 31,
(in millions) |  | 2020 |  | 2019
Change in benefit obligation: | ​ | ​ | ​ | ​ | ​ | ​
Projected benefit obligation at beginning of year | ​ | $ | 20.6 | ​ | $ | 11.9
Interest cost | ​ |  | 1.3 | ​ |  | 0.9
Actuarial loss/ (gain)-claims cost | ​ |  | — | ​ |  | —
Benefits paid | ​ |  | (1.5) | ​ |  | (1.3)
Actuarial (gain)/loss | ​ |  | 4.5 | ​ |  | 8.6
Inflation adjustment | ​ |  | (1.1) | ​ |  | 0.5
Projected benefit obligation at end of year | ​ | $ | 23.8 | ​ | $ | 20.6
Change in plan assets: | ​ | ​ | ​ | ​ | ​ | ​
Fair value of plan assets at beginning of year | ​ | $ | — | ​ | $ | —
Employer contributions | ​ |  | 0.1 | ​ |  | 0.1
Benefits paid | ​ |  | (0.1) | ​ |  | (0.1)
Fair value of plan assets at end of year | ​ | $ | — | ​ | $ | —
Funded status at end of year: | ​ | $ | 23.8 | ​ | $ | 20.6
ASC-715 amounts recognized in statement of financial position consists of: | ​ | ​ | ​ | ​ | ​ | ​
Current liabilities | ​ | $ | — | ​ | $ | (0.1)
Non-current liabilities | ​ |  | (23.8) | ​ |  | (20.5)
Total | ​ | $ | (23.8) | ​ | $ | (20.6)
ASC-715 amounts recognized in accumulated other comprehensive income consists of: | ​ | ​ | ​ | ​ | ​ | ​
Net loss (gain) | ​ | $ | 4.6 | ​ | $ | 1.5
Total (net of income taxes of $(1.9) million and $(0.7) million in 2020 and 2019, respectively) | ​ | $ | 4.6 | ​ | $ | 1.5
​
Schedule of changes in accumulated other comprehensive income | ​
​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | As of December 31,
(in millions) |  | 2020 |  | 2019
Reconciliation of accumulated other comprehensive income: | ​ | ​ | ​ | ​ | ​ | ​
Accumulated other comprehensive income at beginning of plan year | ​ | $ | 1.5 | ​ | $ | (4.4)
Net loss/(gain) occurring during the year | ​ |  | 3.2 | ​ |  | 6.0
Net loss/(gain) amortized during the year | ​ |  | — | ​ |  | 0.1
Currency exchange rate adjustment | ​ |  | (0.1) | ​ |  | (0.2)
Net adjustment to accumulated other comprehensive income (net of income taxes of $(1.2) million and $(2.6) million in 2020 and 2019, respectively) | ​ |  | 3.1 | ​ |  | 5.9
Accumulated other comprehensive income at end of plan year | ​ | $ | 4.6 | ​ | $ | 1.5
​
Summary of the amounts in accumulated other comprehensive income amortized and recognized as a component of net periodic benefit cost, net of tax | ​
​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | As of December 31,
(in millions) |  | 2020 |  | 2019
Net loss / (gain) | ​ | $ | 3.2 | ​ | $ | 5.9
Amortization of net (loss) gain | ​ |  | — | ​ |  | 0.2
Total amortization expenses | ​ | $ | 3.2 | ​ | $ | 6.1
​
Schedule of assumptions used to determine the pension obligations and other post-retirement benefits | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ |  | 2020 |  | 2019 |  | 2018 |
Expatriate health plan | ​ | ​ | ​ | ​ | ​ | ​ | ​
Discount rate |  | 1.90 | % | 2.85 | % | 3.90 | %
Mexican health plan | ​ | ​ | ​ | ​ | ​ | ​ | ​
Weighted average discount rate |  | 7.43 | % | 7.15 | % | 8.45 | %
Scheduled maturities of the benefits expected to be paid in each of the next five years, and thereafter | ​
​ | ​ | ​ | ​
​ |  | Expected
Year | ​ | Benefit Payments
​ | ​ | (in millions)
2021 | ​ | $ | 1.5
2022 | ​ | ​ | 1.6
2023 | ​ |  | 1.5
2024 | ​ |  | 1.5
2025 | ​ |  | 1.6
2026 to 2030 | ​ |  | 8.6
Total | ​ | $ | 16.3
​
Mexican Health Plan | Post retirement defined benefit plans and defined contribution plan |
Components of net periodic benefit costs |
Schedule of asset mix of the investment portfolio | ​
​ | ​ | ​ | ​ | ​ | ​
​ |  | 2020 |  | 2019 |
Asset category: | ​ | ​ | ​ | ​ | ​
Treasury bills |  | 78 | % | 80 | %
Equity securities |  | 22 | % | 20 | %
​ |  | 100 | % | 100 | %
​
Mexican Health Plan | Post-retirement Health care plans |
Components of net periodic benefit costs |
Schedule of effects of one percentage-point change in assumed other benefits cost trend rates | ​
​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | One Percentage
​ | ​ | Point
(in millions) |  | Increase |  | Decrease
Effect on total service and interest cost components | ​ | $ | 1.9 | ​ | $ | 1.5
Effect on the post-retirement benefit obligation | ​ | $ | 24.7 | ​ | $ | 22.2

X
- Definition Tabular disclosure of the amount in accumulated other comprehensive income recognized as a component of net periodic benefit cost. + References No definition available. + Details
Name: | scco_ScheduleOfAmountsInAccumulatedOtherComprehensiveIncomeLossRecognizedAsComponentOfNetPeriodicCostTableTextBlock
Namespace Prefix: | scco_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the change in the benefit obligation and fair value of the assets of pension plans from the beginning to the end of the period, showing separately, if applicable, the effects of the following: service cost, interest cost, contributions by plan participants, actuarial gains and losses, foreign currency exchange rate changes, benefits paid, plan amendments, business combinations, divestitures, curtailments, settlements, and special and contractual termination benefits. This also includes amount recognized in balance sheet and accumulated other comprehensive income. + References No definition available. + Details
Name: | scco_ScheduleOfChangesInBenefitObligationAndPlanAssetsAndAmountRecognizedInFinancialStatementsTableTextBlock
Namespace Prefix: | scco_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the changes in accumulated other comprehensive income related to the defined benefit plan. + References No definition available. + Details
Name: | scco_ScheduleOfDefinedBenefitPlanChangesInAccumulatedOtherComprehensiveIncomeLossTableTextBlock
Namespace Prefix: | scco_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the major categories of plan assets of pension plans and/or other employee benefit plans. This information may include, but is not limited to, the target allocation of plan assets, the fair value of each major category of plan assets, and the level within the fair value hierarchy in which the fair value measurements fall. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(5) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
Name: | us-gaap_ScheduleOfAllocationOfPlanAssetsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of assumption used to determine benefit obligation and net periodic benefit cost of defined benefit plan. Includes, but is not limited to, discount rate, rate of compensation increase, expected long-term rate of return on plan assets and interest crediting rate. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (k) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
Name: | us-gaap_ScheduleOfAssumptionsUsedTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the effect of a one-percentage-point increase and the effect of a one-percentage-point decrease in the assumed health care cost trend rates on the aggregate of the service and interest cost components of net periodic postretirement health care benefit costs and the accumulated postretirement benefit obligation for health care benefits. + References Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (m) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
Name: | us-gaap_ScheduleOfEffectOfOnePercentagePointChangeInAssumedHealthCareCostTrendRatesTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of benefits expected to be paid by pension plans and/or other employee benefit plans in each of the next five fiscal years and in the aggregate for the five fiscal years thereafter. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
Name: | us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the components of net benefit costs for pension plans and/or other employee benefit plans including service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) recognized due to settlements or curtailments. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
Name: | us-gaap_ScheduleOfNetBenefitCostsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=scco_DefinedBenefitPostretirementHealthCarePlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PlanNameAxis=scco_MexicanPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |