Accounting Standards - Revenue Recognition Standard (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues and other income:
Revenues from contracts with customers	$ 1,538	$ 1,136	$ 4,522	$ 2,911
Marketing revenues		48		117
Other income	119	8	135	31
Costs and expenses:
Marketing, including purchases from related parties		49		121
Shipping, handling and other operating	152	$ 109	408	$ 309
Presentation without adoption of ASC Topic 606
Revenues and other income:
Revenues from contracts with customers	1,536		4,518
Marketing revenues	47		122
Other income	118		132
Costs and expenses:
Marketing, including purchases from related parties	46		122
Shipping, handling and other operating	150		401
Accounting Standards Update 2014-09 | Adjustments
Revenues and other income:
Revenues from contracts with customers	(2)		(4)
Marketing revenues	47		122
Other income	(1)		(3)
Costs and expenses:
Marketing, including purchases from related parties	46		122
Shipping, handling and other operating	$ (2)		$ (7)