Nuclear Decommissioning Trust Fund

NRG's nuclear decommissioning trust fund assets, which are for its portion of the decommissioning of the South Texas Project, or STP Units 1 & 2, are comprised of securities classified as available-for-sale and recorded at fair value based on actively quoted market prices. NRG accounts for the nuclear decommissioning trust fund in accordance with ASC 980, Regulated Operations, or ASC 980, because the Company's nuclear decommissioning activities are subject to approval by the PUCT with regulated rates that are designed to recover all decommissioning costs and that can be charged to and collected from the ratepayers per PUCT mandate. Since the Company is in compliance with PUCT rules and regulations regarding decommissioning trusts and the cost of decommissioning is the responsibility of the Texas ratepayers, not NRG, all realized and unrealized gains or losses (including other-than-temporary impairments) related to the Nuclear Decommissioning Trust Fund are recorded to the Nuclear Decommissioning Trust Liability and are not included in net income or accumulated other comprehensive income, consistent with regulatory treatment.

The following table summarizes the aggregate fair values and unrealized gains and losses (including other-than-temporary impairments) for the securities held in the trust funds, as well as information about the contractual maturities of those securities.



	As of September 30, 2012							As of December 31, 2011
(In millions, except otherwise noted)	Fair Value		Unrealized Gains		Unrealized Losses		Weighted- average maturities (in years)	Fair Value		Unrealized Gains		Unrealized Losses		Weighted- average maturities (in years)
Cash and cash equivalents	$	4	$	—	$	—	—	$	2	$	—	$	—	—
U.S. government and federal agency obligations	33		2		—		11	43		3		—		10
Federal agency mortgage-backed securities	63		3		—		23	63		3		—		23
Commercial mortgage-backed securities	6		—		—		29	7		—		—		28
Corporate debt securities	72		4		—		11	54		3		1		10
Equity securities	286		143		—		—	251		113		1		—
Foreign government fixed income securities	5		—		—		6	4		—		—		8
Total	$	469	$	152	$	—		$	424	$	122	$	2

The following table summarizes proceeds from sales of available-for-sale securities and the related realized gains and losses from these sales. The cost of securities sold is determined on the specific identification method.



	Nine months ended September 30,
	2012		2011
	(In millions)
Realized gains	$	8	$	4
Realized losses	5		3
Proceeds from sale of securities	316		294