Investments

3 Months Ended

Mar. 31, 2016

Regulated Entity, Other Assets, Noncurrent [Abstract]

Investments

Investments

Nuclear Decommissioning Trusts

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):

	Longest Maturity Dates	Amortized Cost				Fair Value
(in millions)		March 31, 2016		December 31, 2015		March 31, 2016		December 31, 2015
Stocks	—	$	311	$	304	$	1,464	$	1,460
Municipal bonds	2054	736		691		894		840
U.S. government and agency securities	2046	1,002		1,070		1,092		1,128
Corporate bonds	2057	662		708		731		755
Short-term investments and receivables/payables1	One-year	106		144		109		148
Total		$	2,817	$	2,917	$	4,290	$	4,331

¹ Short-term investments include $8 million and $81 million of repurchase agreements payable by financial institutions which earn interest, are fully secured by U.S. Treasury securities and mature by April 4, 2016 and January 5, 2016 as of March 31, 2016 and December 31, 2015, 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 $1.5 billion and $1.4 billion at March 31, 2016 and December 31, 2015, respectively.

The following table sets forth a summary of changes in the fair value of the trust:

	Three months ended March 31,
(in millions)	2016			2015
Balance at beginning of period	$	4,331		$	4,799
Gross realized gains	17			27
Gross realized losses	(3		)	(2		)
Unrealized gains, net	59			44
Other-than-temporary impairments	(7		)	(4		)
Interest and dividends	29			28
Contributions	—			7
Income taxes	(18		)	—
Decommissioning disbursements	(116		)	—
Administrative expenses and other	(2		)	(3		)
Balance at end of period	$	4,290		$	4,896

Trust assets are used to pay income taxes as the Trust files separate income taxes returns from SCE. Deferred income taxes related to unrealized gains at March 31, 2016 were $357 million. Accordingly, the fair value of Trust assets available to pay future decommissioning costs, net of deferred income taxes, totaled $3.9 billion at March 31, 2016. Due to regulatory mechanisms, changes in assets of the trusts from income or loss items have no impact on operating revenue or earnings.