Future decommissioning costs related to SCE's nuclear assets are expected to be funded from independent decommissioning trusts.

The following table sets forth amortized cost and fair value of the trust investments (see Note 4 for a discussion of fair value of the trust investments):

1	Short-term investments include $37 million and $138 million of repurchase agreements payable by financial institutions which earn interest, are fully secured by U.S. Treasury securities and mature by January 3, 2022 and January 4, 2021 as of December 31, 2021 and 2020, respectively.

Trust fund earnings (based on specific identification) increase the trust fund balance and the ARO regulatory liability. Unrealized holding gains, net of losses, were $2.1 billion at both December 31, 2021 and 2020.

Trust assets are used to pay income taxes. Deferred tax liabilities related to net unrealized gains were $517 million and $515 million at December 31, 2021 and 2020, respectively. Accordingly, the fair value of trust assets available to pay future decommissioning costs, net of deferred income taxes, totaled $4.4 billion and $4.3 billion at December 31, 2021 and 2020, respectively.

The following table summarizes the gains and losses for the trust investments:


	December 31,
(in millions)	2021		2020		2019
Gross realized gains	$	339	$	255	$	87
Gross realized losses		(24)		(6)		(2)
Net unrealized gains for equity securities		103		176		343

Due to regulatory mechanisms, changes in assets of the trusts from income or loss items have no impact on operating revenue or earnings.

Edison International Parent and Other's Investments

Edison International Parent and Other holds strategic investments in companies focused on developing electric technologies and services. As of December 31, 2021, these investments consist of $12 million of marketable securities, and $3 million of equity investments without readily determinable fair values (included as "Other investments" on Edison International's consolidated balance sheets). The unrealized gains for equity investments held as of December 31, 2021 is $4 million for the year ended December 31, 2021, recorded as "Other income" on Edison International's consolidated statement of income. For further information, see Note 4 and Note 16.