Summary of Significant Accounting Policies - Turnaround Expenses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Petroleum Segment
Planned Major Maintenance Activities [Line Items]
Amortization period	4 years
Turnaround costs capitalized	$ 8	$ 155	$ 38
Petroleum Segment \| Minimum
Planned Major Maintenance Activities [Line Items]
Frequency of planned major maintenance activities	4 years
Petroleum Segment \| Maximum
Planned Major Maintenance Activities [Line Items]
Frequency of planned major maintenance activities	5 years
Nitrogen Fertilizer Segment
Planned Major Maintenance Activities [Line Items]
Turnaround expenses incurred	$ 3	$ 1	$ 10
Nitrogen Fertilizer Segment \| Minimum
Planned Major Maintenance Activities [Line Items]
Frequency of planned major maintenance activities	2 years
Nitrogen Fertilizer Segment \| Maximum
Planned Major Maintenance Activities [Line Items]
Frequency of planned major maintenance activities	3 years