Table of Contents 11. Investments in debt and equity securities We have investments in certain debt and equity securities, primarily at Insurance Services, which we record at fair value and primarily include in Other assets in Statement 3. We classify debt securities as available-for-sale, and we include the unrealized gains and losses arising from the revaluation of these debt securities, net of applicable deferred income taxes, in equity (Accumulated other comprehensive income (loss) in Statement 3). We include the unrealized gains and losses arising from the revaluation of the equity securities in Other income (expense) in Statement 1. We generally determine realized gains and losses on sales of investments using the specific identification method for debt and equity securities and include them in Other income (expense) in Statement 1. The cost basis and fair value of debt securities with unrealized gains and losses included in equity (Accumulated other comprehensive income (loss) in Statement 3) were as follows: As of December 31, 2020, there was no available-for-sale investments with net losses in accumulated other comprehensive income. As of December 31, 2019, the total unrealized loss for available-for-sale investments in an unrealized loss position that were not other-than temporarily impaired was $1 million. The cost basis and fair value of the available-for-sale debt securities at December 31, 2020, by contractual maturity, are shown below. Expected maturities will differ from contractual maturities because borrowers may have the right to prepay and creditors may have the right to call obligations. 109 December 31, 2020 (Millions of dollars) Cost Basis Fair Value Due in one year or less $ 135 $ 136 Due after one year through five years 702 737 Due after five years through ten years 279 295 Due after ten years 70 72 U.S. governmental agency mortgage-backed securities 362 374 Residential mortgage-backed securities 5 5 Commercial mortgage-backed securities 60 64 Total debt securities – available-for-sale $ 1,613 $ 1,683 December 31, 2020 December 31, 2019 (Millions of dollars) Cost Basis Unrealized Pretax Net Gains (Losses) Fair Value Cost Basis Unrealized Pretax Net Gains (Losses) Fair Value Government debt U.S. treasury bonds $ 10 $ — $ 10 $ 9  $ —  $ 9  Other U.S. and non-U.S. government bonds 58 1 59 54  —  54  Corporate bonds Corporate bonds 962 50 1,012 836  20  856  Asset-backed securities 156 3 159 62  —  62  Mortgage-backed debt securities U.S. governmental agency 362 12 374 327  4  331  Residential 5 — 5 6  —  6  Commercial 60 4 64 46  1  47  Total debt securities $ 1,613 $ 70 $ 1,683 $ 1,340  $ 25  $ 1,365 