Employee Benefit Plans - PAC - Multiemployer and Joint Trust Pension Plans (Details) - PAC - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Jan. 31, 2024
Defined Benefit Plan Disclosure [Line Items]
Percentage by which joint trustee plan was at least funded	80.00%	80.00%	80.00%
Contributions	$ 5	$ 6	$ 6
UMWA Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Withdrawal liability	$ 115
UMWA Pension Plan | Subsequent event
Defined Benefit Plan Disclosure [Line Items]
Withdrawal liability				$ 80