Revenue Disaggregation of revenue (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenues		$ 4,607		$ 8,356
Other Motor Fuels [Member]
Revenues	[1]	203		648
Continuing Operations [Member]
Other		66	$ 185	242	$ 353
Revenues		4,607	2,892	8,356	5,700
Continuing Operations [Member] | Fuel Distribution and Marketing [Member]
Revenues		4,350		7,489
Continuing Operations [Member] | Fuel Distribution and Marketing [Member] | Operating Segments [Member]
Other		15	12	29	24
Revenues		4,803	2,668	8,300	5,294
Continuing Operations [Member] | All Other [Member]
Other		51		213
Revenues		257		867
Continuing Operations [Member] | All Other [Member] | Operating Segments [Member]
Other		51	173	213	329
Revenues		287	599	931	1,145
Continuing Operations [Member] | Wholesale motor fuel sales to third parties [Member]
Revenues		983
Continuing Operations [Member] | Distributor Revenue [Member]
Revenues		2,207
Continuing Operations [Member] | Unbranded Wholesale Revenue [Member]
Revenues		687
Continuing Operations [Member] | Commission Agent Revenue [Member]
Revenues		427
Continuing Operations [Member] | Rental and Other [Member]
Revenues		34	22	56	44
Continuing Operations [Member] | Rental and Other [Member] | Fuel Distribution and Marketing [Member]
Revenues		31		50
Continuing Operations [Member] | Rental and Other [Member] | Fuel Distribution and Marketing [Member] | Operating Segments [Member]
Revenues		31	19	50	38
Continuing Operations [Member] | Rental and Other [Member] | All Other [Member]
Revenues		3		6
Continuing Operations [Member] | Rental and Other [Member] | All Other [Member] | Operating Segments [Member]
Revenues		$ 3	$ 3	$ 6	$ 6

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