Amortization expense related to amortizable intangible assets  — 2014 2013 2012 Charged to cost of sales $ 7 $ 13 $ 13 Charged to amortization of intangibles 42 74 74 Total amortization $ 49 $ 87 $ 87 The following table provides the estimated aggregate pre-tax amortization expense related to intangible assets for each of  the next five years based on December 31, 2014 exchange rates. Actual amounts may differ from these estimates due to such  factors as currency translation, customer turnover , impairments, additional intangible asset acquisitions and other events. 2015 2016 2017 2018 2019 Amortization expense $ 19 $ 17 $ 15 $ 12 $ 10 Note 5. Restructuring of Operations Our restructuring activities primarily include rationalizing our operating footprint by consolidating facilities, positioning  operations in lower cost locations and reducing overhead costs. Restructuring expense includes costs associated with current  and previously announced actions and is comprised of contractual and noncontractual separation costs and exit costs, including  costs associated with lease continuation obligations and certain operating costs of facilities that we are in the process of closing. During 2014, we implemented various cost reduction programs, including the closure of our Commercial  Vehicle foundry  in Argentina and other headcount reduction programs in our Light  Vehicle and Commercial Vehicle businesses in South  America and Europe. Total restructuring expense in 2014 associated with these actions and with other previously announced  initiatives was $21 and included $15 of severance and related benefits costs and $ 6 of exit costs. During 2013, we implemented certain headcount reduction programs, primarily in our Light  Vehicle and Commercial  Vehicle businesses in Argentina and Australia and in our Off-Highway business in Europe. New customer programs and other  developments in our North American Light Vehicle business and a decision by our European Of f-Highway business to in- source the manufacturing of certain parts resulted in the reversal of previously accrued severance obligations. Excluding  $1 of  exit costs associated with discontinued operations, restructuring expense in 2013 was  $24, net of the aforementioned reversals,  and was attributable to the cost of newly implemented and previously announced initiatives. Restructuring expense includes  $14 of severance and related benefits costs and  $10 of exit costs. During 2012, we implemented certain cost reduction programs, including headcount reduction initiatives at several of our  manufacturing operations in all regions, the most significant of which impacted the Light  Vehicle and Commercial Vehicle  businesses in South America and Europe. Included in these actions was the planned closure of our Light  Vehicle manufacturing  facility in Austria, which was completed during 2013. Additionally, we exited our Commercial Vehicle facility in Kalamazoo,  Michigan in June 2012 and recognized the fair value of the associated lease continuation obligation. Excluding  $3 of exit costs  associated with discontinued operations, restructuring expense in 2012 to recognize the costs of these actions and those of  previously announced initiatives was $47 and included $27 of severance and related benefit costs and  $20 of exit costs. 53