Segment Reporting Disaggregation of Revenue (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Energy Segment
Disaggregation of Revenue [Line Items]
Disaggregated revenue	$ 3,930	$ 6,364	$ 7,124
Automotive Segment
Disaggregation of Revenue [Line Items]
Disaggregated revenue	2,478	2,884	2,858
Petroleum products \| Energy Segment
Disaggregation of Revenue [Line Items]
Disaggregated revenue	3,580	5,960	6,773
Nitrogen fertilizer products \| Energy Segment
Disaggregation of Revenue [Line Items]
Disaggregated revenue	350	404	351
Automotive services \| Automotive Segment
Disaggregation of Revenue [Line Items]
Disaggregated revenue	1,228	1,373	1,321
Automotive parts [Member] \| Automotive Segment
Disaggregation of Revenue [Line Items]
Disaggregated revenue	$ 1,250	$ 1,511	$ 1,537

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130543-203045

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130545-203045

Name:	us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration