Separation of Retail Business (Details) (USD $)	9 Months Ended		0 Months Ended		1 Months Ended	3 Months Ended		0 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	May 01, 2013 Spinoff [Member]	Apr. 30, 2013 Spinoff [Member]	Nov. 30, 2013 Spinoff [Member]	Jun. 30, 2013 Spinoff [Member]	May 01, 2013 Spinoff [Member]	May 01, 2013 Spinoff [Member] Notes Payable to Banks [Member]	Apr. 16, 2013 Spinoff [Member] Notes Payable to Banks [Member]
Separation of Retail Business (Textual)
Spinoff transaction, ownership percentage by Valero stockholders							80.00%
Aggregate proceeds received related to separation of CST Brands, Inc.							$ 1,050,000,000
Proceeds from short-term debt in anticipation of separation	0	550,000,000							550,000,000
Cash distributed to Valero by CST Brands, Inc.	0	500,000,000	500,000,000
Senior unsecured bonds of CST Brands, Inc. issued to us							550,000,000
CST Brands, Inc. securities exchanged in settlement of short-term borrowings								550,000,000
Cash held and retained by CST Brands, Inc. upon separation	0	315,000,000		315,000,000
Cost of separation in general and administrative expense						$ 30,000,000
Retained ownership percentage disposed					20.00%