Inventories (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015
Schedule of Inventories
Refinery feedstocks	$ 2,318		$ 2,068
Refined petroleum products and blendstocks	3,189		3,153
Ethanol feedstocks and products	268		238
Materials and supplies	250		250
Inventories	6,025		5,709
Inventories (Textual)
Lower of cost or market inventory valuation reserve				$ 766
Lower of cost or market inventory valuation adjustment	0	$ 293
Excess of market value over carrying amount of LIFO inventories	1,800		1,900
Amount of non-LIFO inventory	$ 663		$ 641