Pension and Savings Plans - Textual (Details)	3 Months Ended	12 Months Ended
	Apr. 01, 2017 numberOfPlan	Dec. 31, 2022	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Number of 401(k) plans | numberOfPlan	3
Paid discretionary contributions to defined contribution pension plans, company match			$ 9,700,000	$ 9,600,000	$ 27,800,000
Discretionary contributions to defined contribution pension plans, granted					0
Payment of prior performance contributions			0	0	8,900,000
Australia
Defined Benefit Plan Disclosure [Line Items]
Paid discretionary contributions to defined contribution pension plans, company match			17,400,000	20,500,000	26,500,000
Discretionary contributions to defined contribution pension plans, granted			0		0
Payment of prior performance contributions			0		3,000,000
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Payment for settlement			0	51,600,000
Settlement gain			0	2,700,000	0
Net actuarial (gain) loss			$ 12,700,000	$ (25,600,000)	$ (16,600,000)
Expected long-term return on plan assets			2.80%	3.60%	4.20%
Accumulated benefit obligation			$ 751,700,000	$ 816,400,000
Defined benefit plan, assets			$ 772,400,000	847,500,000	$ 855,200,000
Percentage of company's qualified pension plans on a GAAP accounting basis			80.00%
Peabody Plan
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, assets			$ 611,600,000	672,500,000
Plan with accumulated benefit obligation in excess of plan assets, accumulated benefit obligation			583,100,000	632,900,000
Western Plan
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, assets			160,800,000	175,000,000
Plan with accumulated benefit obligation in excess of plan assets, accumulated benefit obligation			$ 168,600,000	$ 183,500,000
Fixed Income Investments
Defined Benefit Plan Disclosure [Line Items]
Plan assets, target allocation, percentage			100.00%	100.00%
Real Estate
Defined Benefit Plan Disclosure [Line Items]
Plan assets, target allocation, percentage			1.00%	1.00%
Scenario, Forecast | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Expected long-term return on plan assets		3.20%