Employee Benefit Plans - Summary of Participants (Details)	Jan. 01, 2020 employee
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Active Employees	3,373
Retirees and Beneficiaries	11,841
Other	3,854
Total	19,068
Post-retirement Medical Plan
Defined Benefit Plan Disclosure [Line Items]
Active Employees	779
Retirees and Beneficiaries	2,282
Other	0
Total	3,061