Table of Contents December 31, 2020 (Millions of dollars) Level 1 Level 2 Level 3 Measured at NAV Total Assets at Fair Value Other Postretirement Benefits Equity securities: U.S. equities $ 88 $ — $ — $ — $ 88 Non-U.S. equities 21 —  — — 21 Fixed income securities: U.S. corporate bonds —  11 — 1 12 Non-U.S. corporate bonds —  2 — — 2 U.S. government bonds —  3 — — 3 U.S. governmental agency mortgage-backed securities —  6 — — 6 Non-U.S. government bonds —  3 — — 3 Cash, short-term instruments and other — 2 — 10 12 Total other postretirement benefit assets $ 109 $ 27 $ — $ 11 $ 147 December 31, 2019 (Millions of dollars) Level 1 Level 2 Level 3 Measured at NAV Total Assets at Fair Value Other Postretirement Benefits Equity securities: U.S. equities $ 119  $ —  $ —  $ —  $ 119  Non-U.S. equities 56  —  —  —  56  Fixed income securities: U.S. corporate bonds —  33  —  —  33  Non-U.S. corporate bonds —  6  —  —  6  U.S. government bonds —  9  —  —  9  U.S. governmental agency mortgage-backed securities —  16  —  —  16  Non-U.S. government bonds —  3  —  —  3  Cash, short-term instruments and other 2  1  —  10  13  Total other postretirement benefit assets $ 177  $ 68  $ —  $ 10  $ 255  118