Summarized Financial Data – Chevron Phillips Chemical Company LLC - Summary of Balance Sheet Information (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Subsidiary Statements Captions [Line Items]
Current assets	$ 26,078	$ 28,329
Current liabilities	22,183	26,530
Total CTC net deficit	132,726	145,208	$ 155,642	$ 149,319
Chevron Phillips Chemical Company LLC
Subsidiary Statements Captions [Line Items]
Current assets	2,816	2,554
Other assets	14,210	14,314
Current liabilities	1,394	1,247
Other liabilities	3,380	3,174
Total CTC net deficit	$ 12,252	$ 12,447