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v3.22.1

Investments (Tables) | 3 Months Ended
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Mar. 31, 2022
Investments [Abstract] |
Amortized Cost and Fair Value of the Trust Investments | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | ​ | ​ | Amortized Cost | ​ | Fair Value | ​
​ | ​ | Longest | ​ | March 31, | ​ | December 31, | ​ | March 31, | ​ | December 31, | ​
(in millions) |  | Maturity Dates |  | 2022 |  | 2021 |  | 2022 |  | 2021 | ​
Stocks |  | — |  | ​ | * |  | ​ | * | ​ | $ | 1,879 | ​ | $ | 1,972 | ​
Municipal bonds |  | 2057 |  | $ | 872 |  | $ | 875 | ​ |  | 955 | ​ |  | 1,033 | ​
Government and agency securities |  | 2067 |  | ​ | 1,023 |  | ​ | 1,095 | ​ |  | 1,092 | ​ |  | 1,212 |
Corporate bonds |  | 2070 |  | ​ | 415 |  | ​ | 386 | ​ |  | 458 | ​ |  | 446 |
Short-term investments and receivables/payables1 |  | One-year |  | ​ | 134 |  | ​ | 199 | ​ |  | 143 | ​ |  | 207 |
Total |  |  | ​ | $ | 2,444 | ​ | $ | 2,555 | ​ | $ | 4,527 | ​ | $ | 4,870 |
* | Not applicable
1 | Short-term investments include $11 million and $37 million of repurchase agreements payable by financial institutions which earn interest, are fully secured by U.S. Treasury securities and mature by April 1, 2022 and January 3, 2022 as of March 31, 2022 and December 31, 2021, respectively.
Summary of gains and losses | ​
​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Three months ended March 31,
(in millions) |  | 2022 |  | 2021
Gross realized gains | ​ | $ | 15 | ​ | $ | 111
Gross realized losses | ​ |  | 16 | ​ |  | 12
Net unrealized (losses) gains for equity securities | ​ |  | (100) | ​ |  | 18

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