ASSETS MEASURED AND RECORDED AT FAIR VALUE ON A NON-RECURRING BASIS Our non-marketable equity securities, equity method investments, and certain non-financial assets, such as intangible assets and property, plant and equipment, are recorded at fair value only if an impairment or observable price adjustment is recognized in the current period.
If an impairment or observable price adjustment is recognized on our non-marketable equity securities during the period, we classify these assets as Level 3 within the fair value hierarchy based on the nature of the fair value inputs.
We classified non-marketable equity securities and non-marketable equity method investments as Level 3.
Impairments recognized on these investments held as of December 29, 2018 were $416 million ($537 million held as of December 30, 2017 and $153 million held as of December 31, 2016).
FINANCIAL INSTRUMENTS NOT RECORDED AT FAIR VALUE ON A RECURRING BASIS Financial instruments not recorded at fair value on a recurring basis include non-marketable equity securities and equity method investments that have not been remeasured or impaired in the current period, grants receivable, loans receivable, reverse repurchase agreements, and our short-term and long-term debt.
Prior to the adoption of the new financial instrument standard, our non-marketable cost method investments were disclosed at fair value on a recurring basis.
The carrying amount and fair value of our non-marketable cost method investments as of December 30, 2017 were $2.6 billion and $3.6 billion, respectively.
These measures are classified as Level 3 within the fair value hierarchy based on the nature of the fair value inputs.
As of December 29, 2018, the aggregate carrying value of grants receivable, loans receivable, and reverse repurchase agreements was $833 million (the aggregate carrying amount as of December 30, 2017 was $935 million).
The estimated fair value of these financial instruments approximates their carrying value and is categorized as Level 2 within the fair value hierarchy based on the nature of the fair value inputs.
For information related to the fair value of our short-term and long-term debt, see “Note 15: Borrowings.
” NOTE 17 : OTHER COMPREHENSIVE INCOME (LOSS) The changes in accumulated other comprehensive income (loss) by component and related tax effects for each period were as follows:
## Table 0 ##
Additional information pertaining to stock option plans is provided in the table below
## Table 1 ##
A summary of nonvested RSU and PSU activity (shares in thousands) is as follows
## Table 2 ##
At December 31, 2015, there was $407 million of total pretax unrecognized compensation expense related to nonvested stock options, RSU and PSU awards which will be recognized over a weighted average period of 1.9 years.
For segment reporting, share-based compensation costs are unallocated expenses.13.
Pension and Other Postretirement Benefit Plans The Company has defined benefit pension plans covering eligible employees in the United States and in certain of its international subsidiaries.
Beginning on January 1, 2013, active participants in Merck’s primary U. S.  defined benefit pension plans are accruing pension benefits using cash balance formulas based on age, service, pay and interest.
However, during a transition period from January 1, 2013 through December 31, 2019, participants will earn the greater of the benefit as calculated under the employee’s legacy final average pay formula or their cash balance formula.
For all years of service after December 31, 2019, participants will earn future benefits under only the cash balance formula.
In addition, the Company provides medical benefits, principally to its eligible U. S.  retirees and their dependents, through its other postretirement benefit plans.
The Company uses December 31 as the year-end measurement date for all of its pension plans and other postretirement benefit plans.
Net Periodic Benefit Cost The net periodic benefit cost for pension and other postretirement benefit plans consisted of the following components
## Table 3 ##
The changes in net periodic benefit cost for pension and other postretirement benefit plans year over year are largely attributable to changes in the discount rate affecting net amortization.
Table of Contents 10 increase in the number of incentives for and use of generic products.
Additionally, improvements in intellectual property laws are sought in the United States and other countries through reform of patent and other relevant laws and implementation of international treaties.
The Company has the following key U. S.  patent protection for drug candidates under review in the United States by the FDA.
Additional patent term may be provided for these pipeline candidates based on Patent Term Restoration and Pediatric Exclusivity.
## Table 4 ##
The Company also has the following key U. S.  patent protection for drug candidates in Phase 3 development:
## Table 5 ##
Unless otherwise noted, the patents in the above charts are compound patents.
Each patent is subject to any future patent term restoration of up to five years and six month pediatric market exclusivity, either or both of which may be available.
In addition, depending on the circumstances surrounding any final regulatory approval of the compound, there may be other listed patents or patent applications pending that could have relevance to the product as finally approved; the relevance of any such application would depend upon the claims that ultimately may be granted and the nature of the final regulatory approval of the product.
Also, regulatory exclusivity tied to the protection of clinical data is complementary to patent protection and, in some cases, may provide more effective or longer lasting marketing exclusivity than a compound’s patent estate.
In the United States, the data protection generally runs five years from first marketing approval of a new chemical entity, extended to seven years for an orphan drug indication and 12 years from first marketing approval of a biological product.
For further information with respect to the Company’s patents, see Item 1A.
“Risk Factors” and Item 8.
“Financial Statements and Supplementary Data,” Note 10.
“Contingencies and Environmental Liabilities” below.
Worldwide, all of the Company’s important products are sold under trademarks that are considered in the aggregate to be of material importance.
Trademark protection continues in some countries as long as used; in other countries, as long as registered.
Registration is for fixed terms and can be renewed indefinitely.
Royalty income in 2015 on patent and know-how licenses and other rights amounted to $221 million.
Merck also incurred royalty expenses amounting to $1.2 billion in 2015 under patent and know-how licenses it holds.
Research and Development The Company’s business is characterized by the introduction of new products or new uses for existing products through a strong research and development program.
Approximately 11,900 people are employed in the Company’s research activities.
Research and development expenses were $6.7 billion in 2015, $7.2 billion in 2014 and
Table of Contents 49 Costs, Expenses and Other
## Table 6 ##
* 100% or greater.
(1) Includes $63 million, $49 million and $279 million of IPR&D impairment charges in 2015, 2014 and 2013, respectively.
Materials and Production Materials and production costs were $14.9 billion in 2015, $16.8 billion in 2014 and $17.0 billion in 2013.
Costs include expenses for the amortization of intangible assets recorded in connection with business acquisitions which totaled $4.7 billion in 2015, $4.2 billion in 2014 and $4.7 billion in 2013.
In addition, expenses for 2015 include $105 million of amortization of purchase accounting adjustments to Cubist’s inventories.
Costs in 2015, 2014 and 2013 also include intangible asset impairment charges of $45 million, $1.1 billion and $486 million, respectively, related to marketed products and other intangibles (see Note 7 to the consolidated financial statements).
The Company may recognize additional non-cash impairment charges in the future related to intangibles that were measured at fair value and capitalized in connection with acquisitions and such charges could be material.
Additionally, costs in 2013 include a $41 million intangible asset impairment charge related to a licensing agreement.
Also included in materials and production are costs associated with restructuring activities which amounted to $361 million, $482 million and $446 million in 2015, 2014 and 2013, respectively, including accelerated depreciation and asset write-offs related to the planned sale or closure of manufacturing facilities.
Separation costs associated with manufacturing-related headcount reductions have been incurred and are reflected in Restructuring costs as discussed below.
Gross margin was 62.2% in 2015 compared with 60.3% in 2014 and 61.5% in 2013.
The amortization of intangible assets and purchase accounting adjustments to inventories, as well as the restructuring and impairment charges noted above reduced gross margin by 13.2 percentage points in 2015, 13.6 percentage points in 2014 and 12.8 percentage points in 2013.
Excluding these impacts, the gross margin improvement in 2015 as compared with 2014 was driven primarily by the favorable effects of foreign exchange and lower inventory write-offs, as well as the net impact of acquisitions and divestitures.
The gross margin decline in 2014 as compared with 2013 was driven primarily by the unfavorable effects of inventory write-offs largely related to Victrelis, as well as by changes in product mix, partially offset by the sale of the U. S.  marketing rights to Saphris.
Marketing and Administrative Marketing and administrative expenses declined 11% in 2015 to $10.3 billion in 2015 largely reflecting the favorable effects from foreign exchange, the prior year divestiture of MCC, additional expenses in the prior year related to the health care reform fee as discussed below, lower restructuring costs, as well as lower selling costs, partially offset by higher promotional spending largely related to product launches, as well as higher costs related to the January acquisition of Cubist and higher acquisition and divestiture-related costs.
Marketing and administrative expenses decreased 3% in 2014 to $11.6 billion driven primarily by lower selling costs and promotional spending, the divestiture of MCC and the favorable effects of foreign exchange, partially offset by an additional year of expense related to the health care reform fee, as well as higher acquisition and divestiture-related costs.
Expenses for 2015, 2014 and 2013 include restructuring costs of $78 million, $200 million and $145 million, respectively, related primarily to accelerated depreciation for facilities to be closed or divested.
Separation costs associated with sales force reductions have been incurred and are reflected in Restructuring costs as discussed below.
Expenses also include $436 million, $234 million and $94 million of acquisition and divestiture-related costs in 2015, 2014 and 2013, respectively, consisting of integration, transaction, and certain other costs related to business acquisitions, including severance costs which are not part of the Company’s formal restructuring programs, as well as transaction and certain other costs related to divestitures.
Table of Contents 66 During the second quarter of 2015, upon evaluation of evolving economic conditions in Venezuela and volatility in the country, combined with a decline in transactions that were settled at the official rate, the Company determined it was unlikely that all outstanding net monetary assets would be settled at the official rate.
Accordingly, during the second quarter of 2015, the Company recorded a charge of $715 million within Other (income) expense, netto devalue its net monetary assets in Venezuela to an amount that represented the Company’s estimate of the U. S.  dollar amount that would ultimately be collected.
During the third quarter of 2015, the Company recorded additional exchange losses of $138 million reflecting the ongoing effect of translating transactions and net monetary assets consistent with the second quarter.
As a result of the further deterioration of economic conditions in Venezuela and continued declines in transactions which were settled at the official rate, in the fourth quarter of 2015, the Company began using the SIMADI rate to report its Venezuelan operations.
The Company also revalued its remaining net monetary assets at the SIMADI rate, which resulted in an additional charge in the fourth quarter of 2015 of $161 million.
Accordingly, at December 31, 2015, the Company had approximately $20 million (U. S.  dollar equivalent at the SIMADI rate) of remaining net monetary assets in its Venezuelan entities, of which the large majority was cash.
Merck’s sales in Venezuela were approximately $625 million in 2015.
The Company has reduced its operations in Venezuela; however, Merck continues to work with the government of Venezuela to import essential medicines into the country.
As a result of transitioning to the SIMADI rate in the fourth quarter of 2015 for purposes of reporting its Venezuelan operations, Merck anticipates that sales in Venezuela in 2016 will be de minimis.
The Company also uses forward exchange contracts to hedge its net investment in foreign operations against movements in exchange rates.
The forward contracts are designated as hedges of the net investment in a foreign operation.
The Company hedges a portion of the net investment in certain of its foreign operations and measures ineffectiveness based upon changes in spot foreign exchange rates.
The effective portion of the unrealized gains or losses on these contracts is recorded in foreign currency translation adjustment within Other Comprehensive Income (“OCI”), and remains in Accumulated Other Comprehensive Income (“AOCI”) until either the sale or complete or substantially complete liquidation of the subsidiary.
The cash flows from these contracts are reported as investing activities in the Consolidated Statement of Cash Flows.
Foreign exchange risk is also managed through the use of foreign currency debt.
The Company’s senior unsecured euro-denominated notes have been designated as, and are effective as, economic hedges of the net investment in a foreign operation.
Accordingly, foreign currency transaction gains or losses due to spot rate fluctuations on the euro-denominated debt instruments are included in foreign currency translation adjustment within OCI.
Interest Rate Risk Management The Company may use interest rate swap contracts on certain investing and borrowing transactions to manage its net exposure to interest rate changes and to reduce its overall cost of borrowing.
The Company does not use leveraged swaps and, in general, does not leverage any of its investment activities that would put principal capital at risk.
At December 31, 2015, the Company was a party to 30 pay-floating, receive-fixed interest rate swap contracts designated as fair value hedges of fixed-rate notes in which the notional amounts match the amount of the hedged fixedrate notes as detailed in the table below.

<table><tr><td>(In Millions)</td><td>Unrealized Holding Gains (Losses) on Available-for-Sale Equity Investments</td><td>Unrealized Holding Gains (Losses) on Derivatives</td><td>Actuarial Valuation and Other Pension Expenses</td><td>Translation Adjustments and Other</td><td>Total</td></tr><tr><td>December 31, 2016</td><td>$2,179</td><td>$-259</td><td>$-1,280</td><td>$-534</td><td>$106</td></tr><tr><td>Other comprehensive income (loss) before reclassifications</td><td>2,765</td><td>605</td><td>275</td><td>-2</td><td>3,643</td></tr><tr><td>Amounts reclassified out of accumulated other comprehensive income (loss)</td><td>-3,433</td><td>-69</td><td>103</td><td>509</td><td>-2,890</td></tr><tr><td>Tax effects</td><td>234</td><td>-171</td><td>-61</td><td>1</td><td>3</td></tr><tr><td>Other comprehensive income (loss)</td><td>-434</td><td>365</td><td>317</td><td>508</td><td>756</td></tr><tr><td>December 30, 2017</td><td>1,745</td><td>106</td><td>-963</td><td>-26</td><td>862</td></tr><tr><td>Impact of change in accounting standards</td><td>-1,745</td><td>24</td><td>-65</td><td>-4</td><td>-1,790</td></tr><tr><td>Opening balance as of December 31, 2017</td><td>—</td><td>130</td><td>-1,028</td><td>-30</td><td>-928</td></tr><tr><td>Other comprehensive income (loss) before reclassifications</td><td>—</td><td>-310</td><td>157</td><td>-16</td><td>-169</td></tr><tr><td>Amounts reclassified out of accumulated other comprehensive income (loss)</td><td>—</td><td>9</td><td>109</td><td>8</td><td>126</td></tr><tr><td>Tax effects</td><td>—</td><td>48</td><td>-56</td><td>5</td><td>-3</td></tr><tr><td>Other comprehensive income (loss)</td><td>—</td><td>-253</td><td>210</td><td>-3</td><td>-46</td></tr><tr><td>December 29, 2018</td><td>$—</td><td>$-123</td><td>$-818</td><td>$-33</td><td>$-974</td></tr></table>
<table><tr><td>Years Ended December 31</td><td>2015</td><td>2014</td><td>2013</td></tr><tr><td>Total intrinsic value of stock options exercised</td><td>$332</td><td>$626</td><td>$374</td></tr><tr><td>Fair value of stock options vested</td><td>30</td><td>35</td><td>42</td></tr><tr><td>Cash received from the exercise of stock options</td><td>485</td><td>1,560</td><td>1,210</td></tr></table>
<table><tr><td></td><td colspan="2">RSUs</td><td colspan="2">PSUs</td></tr><tr><td></td><td>Numberof Shares</td><td>WeightedAverageGrant DateFair Value</td><td>Numberof Shares</td><td>WeightedAverageGrant DateFair Value</td></tr><tr><td>Nonvested January 1, 2015</td><td>15,634</td><td>$46.66</td><td>1,882</td><td>$52.81</td></tr><tr><td>Granted</td><td>4,562</td><td>59.66</td><td>909</td><td>51.84</td></tr><tr><td>Vested</td><td>-5,774</td><td>39.45</td><td>-743</td><td>44.58</td></tr><tr><td>Forfeited</td><td>-1,022</td><td>52.64</td><td>-164</td><td>55.66</td></tr><tr><td>Nonvested December 31, 2015</td><td>13,400</td><td>$53.73</td><td>1,884</td><td>$55.33</td></tr></table>
<table><tr><td></td><td colspan="6">Pension Benefits</td><td></td><td></td><td></td></tr><tr><td></td><td colspan="3">U.S.</td><td colspan="3">International</td><td colspan="3">Other Postretirement Benefits</td></tr><tr><td>Years Ended December 31</td><td>2015</td><td>2014</td><td>2013</td><td>2015</td><td>2014</td><td>2013</td><td>2015</td><td>2014</td><td>2013</td></tr><tr><td>Service cost</td><td>$307</td><td>$300</td><td>$386</td><td>$251</td><td>$266</td><td>$296</td><td>$80</td><td>$78</td><td>$102</td></tr><tr><td>Interest cost</td><td>434</td><td>425</td><td>402</td><td>206</td><td>269</td><td>263</td><td>110</td><td>115</td><td>107</td></tr><tr><td>Expected return on plan assets</td><td>-819</td><td>-782</td><td>-721</td><td>-379</td><td>-416</td><td>-376</td><td>-143</td><td>-139</td><td>-126</td></tr><tr><td>Net amortization</td><td>158</td><td>74</td><td>251</td><td>104</td><td>59</td><td>85</td><td>-59</td><td>-71</td><td>-50</td></tr><tr><td>Termination benefits</td><td>22</td><td>53</td><td>51</td><td>1</td><td>11</td><td>7</td><td>7</td><td>22</td><td>50</td></tr><tr><td>Curtailments</td><td>-12</td><td>-69</td><td>-22</td><td>-9</td><td>-4</td><td>-1</td><td>-19</td><td>-39</td><td>-11</td></tr><tr><td>Settlements</td><td>1</td><td>11</td><td>1</td><td>12</td><td>6</td><td>22</td><td>—</td><td>—</td><td>—</td></tr><tr><td>Net periodic benefit cost (credit)</td><td>$91</td><td>$12</td><td>$348</td><td>$186</td><td>$191</td><td>$296</td><td>$-24</td><td>$-34</td><td>$72</td></tr></table>
<table><tr><td>Under Review</td><td>Currently AnticipatedYear of Expiration (in the U.S.)</td></tr><tr><td>V419 (pediatric hexavalent combination vaccine)</td><td>2020 (method of making/vectors)</td></tr><tr><td>MK-6072 (bezlotoxumab)</td><td>2025</td></tr></table>
<table><tr><td>Phase 3 Drug Candidate</td><td rowspan="8">Currently AnticipatedYear of Expiration (in the U.S.) 2016 (use) 2023 2024 2025 2026 (use) 2027 2029</td></tr><tr><td>V212 (inactivated varicella zoster virus (VZV) vaccine)</td></tr><tr><td>V920 (ebola vaccine)</td></tr><tr><td>MK-0822 (odanacatib)</td></tr><tr><td>MK-8228 (letermovir)</td></tr><tr><td>MK-8237 (allergy, house dust mites)</td></tr><tr><td>MK-0859 (anacetrapib)</td></tr><tr><td>MK-7655A (relebactam + imipenem/cilastatin)</td></tr><tr><td>MK-3102 (omarigliptin)</td><td>2030</td></tr><tr><td>MK-8931 (verubecestat)</td><td>2030</td></tr><tr><td>MK-8835 (ertugliflozin)</td><td>2030</td></tr><tr><td>MK-8835A (ertugliflozin + sitagliptin)</td><td>2030</td></tr><tr><td>MK-8835B (ertugliflozin + metformin)</td><td>2030</td></tr><tr><td>MK-1439 (doravirine)</td><td>2031</td></tr><tr><td>MK-8342B (contraception, next generation ring)</td><td>2034</td></tr></table>
<table><tr><td>($ in millions)</td><td>2015</td><td>Change</td><td>2014</td><td>Change</td><td>2013</td></tr><tr><td>Materials and production</td><td>$14,934</td><td>-11%</td><td>$16,768</td><td>-1%</td><td>$16,954</td></tr><tr><td>Marketing and administrative</td><td>10,313</td><td>-11%</td><td>11,606</td><td>-3%</td><td>11,911</td></tr><tr><td>Research and development<sup>-1</sup></td><td>6,704</td><td>-7%</td><td>7,180</td><td>-4%</td><td>7,503</td></tr><tr><td>Restructuring costs</td><td>619</td><td>-39%</td><td>1,013</td><td>-41%</td><td>1,709</td></tr><tr><td>Other (income) expense, net</td><td>1,527</td><td>*</td><td>-11,613</td><td>*</td><td>411</td></tr><tr><td></td><td>$34,097</td><td>37%</td><td>$24,954</td><td>-35%</td><td>$38,488</td></tr></table>

Question: In the year with largest amount of Service cost, what's the sum of Interest cost?
Answer: 772