Segment Reporting Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Energy Segment
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 1,622	$ 1,935	$ 4,794	$ 5,386
Automotive Segment
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	744	735	2,181	2,158
Petroleum products | Energy Segment
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,533	1,855	4,476	5,133
Nitrogen fertilizer products | Energy Segment
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	89	80	318	253
Automotive services | Automotive Segment
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	356	341	1,028	992
Aftermarket parts sales | Automotive Segment
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 388	$ 394	$ 1,153	$ 1,166