11. Segment and Geographic Area Information

In the first quarter of 2018, we revised our reportable segments to consist of the following three segments: Clean Air, Ride Performance and Aftermarket. The new reportable segments, which are also our operating segments, align with how the Chief Operating Decision Maker allocates resources and assesses performance against our key growth strategies. Costs related to other business activities, primarily corporate headquarter functions, are disclosed separately from the three operating segments as “Other.” We evaluate segment performance based primarily on earnings before interest expense, income taxes, and noncontrolling interests. Products are transferred between segments and geographic areas on a basis intended to reflect as nearly as possible the “market value” of the products. Prior period segmentation has been retrospectively recast to reflect our current segmentation.

Segment results for 2017, 2016 and 2015 are as follows:


	Segments
	Clean Air		Ride Performance		Aftermarket		Total		Other			Reclass & Elims			Total
	(Millions)
At December 31, 2017, and for the Year Ended
Revenues from external customers	$	6,216	$	1,807	$	1,251	$	9,274	$	—		$	—		$	9,274
Intersegment revenues		65		60		40		165		—			(165	)		—
EBIT, Earnings (loss) before interest expense, income taxes, and noncontrolling interests		421		61		178		660		(243	)		—			417
Total assets		2,812		1,155		812		4,779					63			4,842
At December 31, 2016, and for the Year Ended
Revenues from external customers	$	5,764	$	1,593	$	1,242	$	8,599	$	—		$	—		$	8,599
Intersegment revenues		108		47		37		192		—			(192	)		—
EBIT, Earnings (loss) before interest expense, income taxes, and noncontrolling interests		432		97		191		720		(204	)		—			516
Total assets		2,559		959		781		4,299		—			47			4,346
At December 31, 2015, and for the Year Ended
Revenues from external customers	$	5,377	$	1,545	$	1,259	$	8,181	$	—		$	—		$	8,181
Intersegment revenues		116		44		42		202		—			(202	)		—
EBIT, Earnings (loss) before interest expense, income taxes, and noncontrolling interests		371		63		174		608		(100	)		—			508
Total assets		2,298		756		884		3,938		—			32			3,970

The following customers accounted for 10 percent or more of our net sales in the last three years. The net sales to both customers were across segments.


Customer	2017			2016			2015
General Motors Company		14	%		17	%		15	%
Ford Motor Company		13	%		13	%		14	%

The following table shows information relating to the geographic regions in which we operate:


	Geographic Area
	United States		China		Germany		Poland		United Kingdom		Other Foreign (a)		Reclass & Elims			Consolidated
	(Millions)
At December 31, 2017, and for the Year Then Ended
Revenues from external customers (b)	$	3,632	$	1,283	$	798	$	488	$	482	$	2,591	$	—		$	9,274
Long-lived assets (c)		620		279		136		216		46		470		—			1,767
Total assets		1,831		988		304		383		205		1,221		(90	)		4,842
At December 31, 2016, and for the Year Then Ended
Revenues from external customers (b)	$	3,512	$	1,186	$	764	$	385	$	387	$	2,365	$	—		$	8,599
Long-lived assets (c)		541		217		111		165		38		397		—			1,469
Total assets		1,897		795		231		322		130		1,119		(148	)		4,346
At December 31, 2015, and for the Year Then Ended
Revenues from external customers (b)	$	3,334	$	1,101	$	807	$	250	$	307	$	2,382	$	—		$	8,181
Long-lived assets (c)		496		203		108		144		32		373		—			1,356
Total assets		1,726		699		258		275		101		1,027		(116	)		3,970

(a)	Revenues from external customers and long-lived assets for individual foreign countries other than China, Germany, Poland, and United Kingdom are not material.

(b)	Revenues are attributed to countries based on location of the shipper.

(c)	Long-lived assets include all long-term assets except goodwill, intangibles and deferred tax assets.