Acquisitions and Investments (Formation of Travel Plaza Joint Venture) (Details) $ in Millions		12 Months Ended
		Dec. 31, 2016 USD ($) Store		Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Schedule of Equity Method Investments [Line Items]
Contribution of fixed assets to joint venture		$ 272	[1]	$ 0	$ 0
PFJ Southeast
Schedule of Equity Method Investments [Line Items]
Convenience stores | Store		123
Contribution of fixed assets to joint venture	[1]	$ 272
PFJ Southeast | Property, Plant and Equipment
Schedule of Equity Method Investments [Line Items]
Contribution of fixed assets to joint venture	[1]	203
PFJ Southeast | Goodwill
Schedule of Equity Method Investments [Line Items]
Contribution of fixed assets to joint venture	[1]	61
PFJ Southeast | Inventories
Schedule of Equity Method Investments [Line Items]
Contribution of fixed assets to joint venture	[1]	$ 8
PFJ Southeast | Speedway
Schedule of Equity Method Investments [Line Items]
Convenience stores | Store		41
PFJ Southeast | Pilot Flying J
Schedule of Equity Method Investments [Line Items]
Convenience stores | Store		82

[1] Speedway’s contribution of travel plaza locations to new joint venture with Pilot Flying J.