The following table reflects the components of operating income by reportable segment (in millions):



	Refining		Ethanol		VLP		Corporate and Eliminations			Total
Three months ended September 30, 2018:
Revenues:
Revenues from external customers	$	29,984	$	864	$	—	$	1		$	30,849
Intersegment revenues	5		68		140		(213		)	—
Total revenues	29,989		932		140		(212		)	30,849
Cost of sales:
Cost of materials and other	27,137		776		—		(212		)	27,701
Operating expenses (excluding depreciation and amortization expense reflected below)	1,047		116		31		(1		)	1,193
Depreciation and amortization expense	466		19		19		—			504
Total cost of sales	28,650		911		50		(213		)	29,398
Other operating expenses	10		—		—		—			10
General and administrative expenses (excluding depreciation and amortization expense reflected below)	—		—		—		209			209
Depreciation and amortization expense	—		—		—		13			13
Operating income by segment	$	1,329	$	21	$	90	$	(221	)	$	1,219

Three months ended September 30, 2017:
Revenues:
Revenues from external customers	$	22,728	$	834	$	—	$	—		$	23,562
Intersegment revenues	1		48		110		(159		)	—
Total revenues	22,729		882		110		(159		)	23,562
Cost of sales:
Cost of materials and other	19,818		669		—		(158		)	20,329
Operating expenses (excluding depreciation and amortization expense reflected below)	996		114		26		(1		)	1,135
Depreciation and amortization expense	455		17		12		—			484
Total cost of sales	21,269		800		38		(159		)	21,948
Other operating expenses	41		—		3		—			44
General and administrative expenses (excluding depreciation and amortization expense reflected below)	—		—		—		225			225
Depreciation and amortization expense	—		—		—		13			13
Operating income by segment	$	1,419	$	82	$	69	$	(238	)	$	1,332



	Refining		Ethanol		VLP		Corporate and Eliminations			Total
Nine months ended September 30, 2018:
Revenues:
Revenues from external customers	$	85,675	$	2,625	$	—	$	3		$	88,303
Intersegment revenues	10		156		407		(573		)	—
Total revenues	85,685		2,781		407		(570		)	88,303
Cost of sales:
Cost of materials and other	77,608		2,279		—		(570		)	79,317
Operating expenses (excluding depreciation and amortization expense reflected below)	3,013		336		93		(3		)	3,439
Depreciation and amortization expense	1,385		57		57		—			1,499
Total cost of sales	82,006		2,672		150		(573		)	84,255
Other operating expenses	41		—		—		—			41
General and administrative expenses (excluding depreciation and amortization expense reflected below)	—		—		—		695			695
Depreciation and amortization expense	—		—		—		39			39
Operating income by segment	$	3,638	$	109	$	257	$	(731	)	$	3,273

Nine months ended September 30, 2017:
Revenues:
Revenues from external customers	$	65,030	$	2,558	$	—	$	—		$	67,588
Intersegment revenues	1		136		326		(463		)	—
Total revenues	65,031		2,694		326		(463		)	67,588
Cost of sales:
Cost of materials and other	57,662		2,166		—		(462		)	59,366
Operating expenses (excluding depreciation and amortization expense reflected below)	2,966		330		75		(1		)	3,370
Depreciation and amortization expense	1,358		63		36		—			1,457
Total cost of sales	61,986		2,559		111		(463		)	64,193
Other operating expenses	41		—		3		—			44
General and administrative expenses (excluding depreciation and amortization expense reflected below)	—		—		—		592			592
Depreciation and amortization expense	—		—		—		39			39
Operating income by segment	$	3,004	$	135	$	212	$	(631	)	$	2,720

The following table provides a disaggregation of revenues by reportable segment (in millions). Refining and ethanol segment revenues are disaggregated for our principal products, and VLP segment revenues are disaggregated by activity type.



	Three Months Ended September 30,						Nine Months Ended September 30,
	2018			2017			2018			2017
Refining:
Gasolines and blendstocks	$	12,664		$	10,310		$	35,810		$	29,368
Distillates	14,052			10,477			41,169			29,909
Other product revenues	3,273			1,942			8,706			5,754
Total refining revenues	29,989			22,729			85,685			65,031
Ethanol:
Ethanol	755			740			2,240			2,290
Distillers grains	177			142			541			404
Total ethanol revenues	932			882			2,781			2,694
VLP:
Pipeline transportation	31			23			93			71
Terminaling	107			86			309			253
Storage and other	2			1			5			2
Total VLP revenues	140			110			407			326
Corporate – other revenues	1			—			3			—
Elimination of intersegment revenues	(213		)	(159		)	(573		)	(463		)
Revenues	$	30,849		$	23,562		$	88,303		$	67,588

Total assets by reportable segment were as follows (in millions):



	September 30, 2018		December 31, 2017
Refining	$	44,168	$	40,382
Ethanol	1,312		1,344
VLP	1,600		1,517
Corporate and eliminations	4,814		6,915
Total assets	$	51,894	$	50,158