Employee Benefit Plan	12 Months Ended
Dec. 31, 2020
Compensation And Retirement Disclosure [Abstract]
Employee Benefit Plan	17. Employee Benefit Plans Nucor makes contributions to a Profit Sharing and Retirement Savings Plan for qualified employees based on the profitability of the Company. Nucor’s expense for these benefits totaled $86.6 million in 2020 ($181.4 million in 2019 and $307.9 million in 2018). The related liability for these benefits is included in salaries, wages and related accruals in the consolidated balance sheets. Nucor also has a medical plan covering certain eligible early retirees. The unfunded obligation, included in deferred credits and other liabilities in the consolidated balance sheets, totaled $28.2 million at December 31, 2020 ($27.0 million at December 31, 2019). The expense associated with this early retiree medical plan totaled $2.5 million in 2020 ($2.0 million in 2019 and $2.1 million in 2018). The discount rate used by Nucor in determining its benefit obligation was 2.40% in 2020 (3.23% in 2019 and 4.24% in 2018). The health care cost increase trend rate used was 5.7% in 2020 (6.0% in 2019 and 6.3% in 2018). The health care cost increase trend rate is projected to decline gradually to 4.5% by 2037.

Employee Benefit Plan

12 Months Ended

Dec. 31, 2020

Compensation And Retirement Disclosure [Abstract]

17. Employee Benefit Plans

Nucor makes contributions to a Profit Sharing and Retirement Savings Plan for qualified employees based on the profitability of the Company. Nucor’s expense for these benefits totaled $86.6 million in 2020 ($181.4 million in 2019 and $307.9 million in 2018). The related liability for these benefits is included in salaries, wages and related accruals in the consolidated balance sheets.

Nucor also has a medical plan covering certain eligible early retirees. The unfunded obligation, included in deferred credits and other liabilities in the consolidated balance sheets, totaled $28.2 million at December 31, 2020 ($27.0 million at December 31, 2019). The expense associated with this early retiree medical plan totaled $2.5 million in 2020 ($2.0 million in 2019 and $2.1 million in 2018). The discount rate used by Nucor in determining its benefit obligation was 2.40% in 2020 (3.23% in 2019 and 4.24% in 2018). The health care cost increase trend rate used was 5.7% in 2020 (6.0% in 2019 and 6.3% in 2018). The health care cost increase trend rate is projected to decline gradually to 4.5% by 2037.