v3.21.2

DEBT (Tables) | 9 Months Ended
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Sep. 30, 2021
Debt Disclosure [Abstract] |
Fair Value and Carrying Value of Debt [Table Text Block] | The estimated fair values and carrying amounts of long-term debt, excluding finance leases, were as follows:
| September 30, 2021 |  | December 31, 2020
| (Thousands of Dollars)
Fair value | $ | 3,668,320 |  |  | $ | 3,799,378 |
Carrying amount | $ | 3,347,960 |  |  | $ | 3,539,258 |

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- Definition Tabular disclosure of information pertaining to carrying amount and estimated fair value of short-term and long-term debt instruments or arrangements, including but not limited to, identification of terms, features, and collateral requirements. + References No definition available. + Details
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