v3.26.1
FAIR VALUE MEASUREMENT: (Tables)
6 Months Ended
Jun. 30, 2026
FAIR VALUE MEASUREMENT:  
Schedule of carrying amount and estimated fair values of the Company's financial instruments Consequently, such financial instruments are not included in the following table, which provides information about the carrying amounts and estimated fair values of other financial instruments that are not measured at fair value in the condensed consolidated balance sheet as of June 30, 2026 and December 31, 2025 (in millions):

As of June 30, 2026

As of December 31, 2025

  ​ ​ ​

Carrying Value

  ​ ​ ​

Fair Value

  ​ ​ ​

Carrying Value

  ​ ​ ​

Fair Value

Liabilities:

Long-term debt level 1

$

7,943.3

$

8,083.2

$

6,699.5

$

7,009.5

Long-term debt level 2

51.2

53.2

51.2

55.1

Total long-term debt

$

7,994.4

$

8,136.4

$

6,750.7

$

7,064.6

Schedule of fair values of assets and liabilities measured at fair value on a recurring basis

Fair values of assets and liabilities measured at fair value on a recurring basis were calculated as follows as of June 30, 2026 and December 31, 2025 (in millions):

Fair Value at Measurement Date Using:

  ​ ​ ​

  ​ ​ ​

  ​ ​ ​

Significant

  ​ ​ ​

Fair Value

Quoted prices in

other

Significant

as of

active markets for

observable

unobservable

June 30, 

identical assets

inputs

inputs

Description

2026

(Level 1)

(Level 2)

(Level 3)

Assets:

Short term investment:

Trading securities

$

1,664.8

$

1,664.8

$

$

Available-for-sale debt securities:

Asset backed securities

 

Mortgage backed securities

 

0.1

0.1

Accounts receivable:

Embedded derivativesNot classified as hedges:

Provisionally priced sales:

Copper

 

1,112.9

 

1,112.9

Molybdenum

442.6

442.6

Zinc

 

81.0

 

81.0

 

Total

$

3,301.4

$

3,301.3

$

0.1

$

Fair Value at Measurement Date Using:

  ​ ​ ​

  ​ ​ ​

  ​ ​ ​

Significant

  ​ ​ ​

Fair Value

Quoted prices in

other

Significant

as of

active markets for

observable

unobservable

December 31, 

identical assets

inputs

inputs

Description

2025

(Level 1)

(Level 2)

(Level 3)

Assets:

Short term investment:

Trading securities

$

604.5

$

604.5

$

$

Available-for-sale debt securities:

Asset backed securities

 

Mortgage backed securities

 

0.1

0.1

Accounts receivable:

Embedded derivatives-Not classified as hedges:

Provisionally priced sales:

Copper

 

1,297.5

 

1,297.5

Molybdenum

383.8

383.8

Zinc

 

80.3

 

80.3

 

Total

$

2,366.3

$

2,366.2

$

0.1

$