Coal Workers' Pneumoconiosis and Workers' Compensation - Schedule of Weighted Average Discount Rates (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
CWP Benefits
Defined Benefit Plan Disclosure [Line Items]
Benefit obligations	5.40%	2.85%	2.53%
Net periodic benefit costs	2.85%	2.53%	3.41%
Workers Compensation
Defined Benefit Plan Disclosure [Line Items]
Benefit obligations	5.38%	2.74%	2.35%
Net periodic benefit costs	2.74%	2.35%	3.25%