Segment Reporting Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Energy Segment
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 1,486	$ 1,537
Automotive Segment
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	693	686
Petroleum products \| Energy Segment
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,394	1,457
Nitrogen fertilizer products \| Energy Segment
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	92	80
Automotive services \| Automotive Segment
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	327	316
Aftermarket parts sales \| Automotive Segment
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 366	$ 370

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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130543-203045

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130539-203045

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130545-203045

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