Quarterly report pursuant to Section 13 or 15(d)


6 Months Ended
Jun. 28, 2020
Investments, Debt and Equity Securities [Abstract]  
A summary of marketable securities, all of which were classified as current, was as follows:
  June 28,
December 31,
In millions Cost
Gross unrealized gains/(losses)(1)
fair value
Gross unrealized gains/(losses)(1)
fair value
Equity securities            
Debt mutual funds $ 221    $   $ 226    $ 180    $   $ 183   
Certificates of deposit 104    —    104    133    —    133   
Equity mutual funds 18      21    19      23   
Bank debentures   —        —     
Debt securities   —        —     
Total marketable securities $ 345    $   $ 353    $ 334    $   $ 341   
(1) Unrealized gains and losses for debt securities are recorded in other comprehensive income while unrealized gains and losses for equity securities are recorded in "Other income, net" in our Condensed Consolidated Statements of Net Income.
All debt securities are classified as available-for-sale. All marketable securities presented use a Level 2 fair value measure. The fair value of Level 2 securities is estimated using actively quoted prices for similar instruments from brokers and observable inputs where available, including market transactions and third-party pricing services, or net asset values provided to investors. We do not currently have any Level 3 securities, and there were no transfers between Level 2 or 3 during the first half of 2020 or for the year ended December 31, 2019.

A description of the valuation techniques and inputs used for our Level 2 fair value measures is as follows:
Debt mutual funds — The fair value measures for the vast majority of these investments are the daily net asset values published on a regulated governmental website. Daily quoted prices are available from the issuing brokerage and are used on a test basis to corroborate this Level 2 input.
Certificates of deposit and bank debentures — These investments provide us with a contractual rate of return and generally range in maturity from three months to five years. The counterparties to these investments are reputable financial institutions with investment grade credit ratings. Since these instruments are not tradable and must be settled directly by us with the respective financial institution, our fair value measure is the financial institution's month-end statement.
Equity mutual funds — The fair value measures for these investments are the net asset values published by the issuing brokerage. Daily quoted prices are available from reputable third-party pricing services and are used on a test basis to corroborate this Level 2 input measure.
Debt securities — The fair value measures for these securities are broker quotes received from reputable firms. These securities are infrequently traded on a national exchange and these values are used on a test basis to corroborate our Level 2 input measure.
The proceeds from sales and maturities of marketable securities were as follows:
Six months ended
In millions June 28,
June 30,
Proceeds from sales of marketable securities $ 164    $ 97   
Proceeds from maturities of marketable securities 90    56   
Investments in marketable securities - liquidations $ 254    $ 153