Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net income	$ 4,156	$ 2,417	$ 4,101
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense	1,986	1,894	1,842
Lower of cost or market inventory valuation adjustment	0	(747)	790
Asset impairment loss	0	56	0
Deferred income tax expense (benefit)	(2,543)	230	165
Changes in current assets and current liabilities	1,289	976	(1,306)
Changes in deferred charges and credits and other operating activities, net	594	(6)	19
Net cash provided by operating activities	5,482	4,820	5,611
Cash flows from investing activities:
Capital expenditures	(1,353)	(1,278)	(1,618)
Deferred turnaround and catalyst costs	(523)	(718)	(673)
Investments in joint ventures	(406)	(4)	(141)
Acquisition of undivided interest	(72)	0	0
Capital expenditures of certain variable interest entities	(26)	0	0
Other investing activities, net	(2)	(6)	(55)
Net cash used in investing activities	(2,382)	(2,006)	(2,487)
Cash flows from financing activities:
Proceeds from debt issuances or borrowings	380	2,153	1,446
Repayments of debt and capital lease obligations	(21)	(1,475)	(513)
Proceeds from the exercise of stock options	10	6	34
Purchase of common stock for treasury	(1,372)	(1,336)	(2,838)
Common stock dividends	(1,242)	(1,111)	(848)
Proceeds from issuance of Valero Energy Partners LP common units	36	10	189
Contributions from noncontrolling interests	30	0	5
Distributions to noncontrolling interests	(67)	(65)	(45)
Other financing activities, net	(26)	(194)	25
Net cash used in financing activities	(2,272)	(2,012)	(2,545)
Effect of foreign exchange rate changes on cash	206	(100)	(154)
Net increase in cash and temporary cash investments	1,034	702	425
Cash and temporary cash investments at beginning of year	4,816	4,114	3,689
Cash and temporary cash investments at end of year	$ 5,850	$ 4,816	$ 4,114