The table below presents the changes of goodwill for the year ended December 31, 2021 based on the Company's reportable segments. Goodwill did not change during the year ended December 31, 2020.


(in millions)	Texas		East		West/Services/Other		Total
Balance as of January 1, 2021	$	324	$	240	$	15	$	579
Goodwill resulted from the acquisition of Direct Energy	427		648		175		1,250
Impairment losses	—		(35)		—		(35)
Foreign currency translation	—		—		1		1
Balance as of December 31, 2021	$	751	$	853	$	191	$	1,795

The Company's intangible assets as of December 31, 2021, primarily reflect intangible assets established with the acquisitions of various companies, including Direct Energy, Stream Energy, other retail acquisitions, and Texas Genco. Intangible assets are comprised of the following:

•Emission Allowances — These intangibles primarily consist of SO2 emission allowances, including those established with the 2006 acquisition of Texas Genco, RGGI emission credits and California carbon allowances. These emission allowances are held-for-use and are amortized to cost of operations based on units of production.

•Customer and supply contracts — These intangibles include the fair value at the acquisition date of in-market and out-of-market customer and supply contracts from the acquisition of Direct Energy and are amortized to revenue and cost of operations, respectively, based upon the fair market value, as of the acquisition date, for each delivery month. It also included energy supply contracts acquired with Stream Energy that represent the fair value at the acquisition date of in-market contracts for the purchase of energy to serve retail electric customers and are amortized based on the expected delivery under the respective contracts.

•Customer relationships — These intangibles represent the fair value at the acquisition date of acquired businesses' customer base from the acquisition of Direct Energy and other acquisitions. The customer relationships are amortized to depreciation and amortization expense based on the expected discounted future net cash flows by year.

•Marketing partnerships — These intangibles represent the fair value at the acquisition date of existing agreements with marketing vendors and loyalty and affinity partners for customer acquisition. The marketing partnerships are amortized to depreciation and amortization expense based on the expected discounted future net cash flows by year.

•Other — These intangibles primarily include renewable energy credits. Renewable energy credits are retired, as required, for the applicable compliance period. They are expensed to cost of operations based on NRG’s customer usage. It also includes in-market nuclear fuel contracts established from the Texas Genco acquisition in 2006 which are amortized to cost of operations over expected volumes over the life of each contract, costs to extend the operating license for STP Units 1 and 2 and intellectual property related to Goal Zero which are amortized to depreciation and amortization expense.


(In millions)
Year Ended December 31, 2021	Emission Allowances		Customer and Supply Contracts		Customer Relationships		Marketing Partnerships		Trade Names		Other(b)		Total
January 1, 2021	$	672	$	28	$	527	$	285	$	373	$	140	$	2,025
Purchases	10		—		—		—		—		338		348
Acquisition of businesses (a)	—		610		1,308		—		310		124		2,352
Usage/Sales/Retirements	(1)		—		—		—		—		(364)		(365)
Write-off of fully amortized balances	(51)		—		(158)		—		—		(7)		(216)

Other	4		—		2		(1)		—		(2)		3
December 31, 2021	634		638		1,679		284		683		229		4,147
Less accumulated amortization	(536)		(94)		(518)		(123)		(294)		(71)		(1,636)
Net carrying amount	$	98	$	544	$	1,161	$	161	$	389	$	158	$	2,511

(a)The weighted average life of total acquired amortizable intangibles from the Direct Energy acquisition was 12 years, see Note 4 — Acquisitions, Discontinued Operations and Dispositions for weighted average life of acquired amortizable intangibles for each intangible asset type


(In millions)
Year Ended December 31, 2020	Emission Allowances		Customer and Supply Contracts		Customer Relationships		Marketing Partnerships		Trade Names		Other(b)		Total
January 1, 2020	$	662	$	28	$	573	$	285	$	373	$	130	$	2,051
Purchases	25		—		—		—		—		45		70
Acquisition of businesses (a)	—		—		22		—		—		—		22
Usage/Retirements	—		—		—		—		—		(35)		(35)
Write-off of fully amortized balances	(4)		—		(70)		—		—		—		(74)
Impairment	(14)		—		—		—		—		—		(14)
Other	3		—		2		—		—		—		5
December 31, 2020	672		28		527		285		373		140		2,025
Less accumulated amortization	(563)		(28)		(349)		(99)		(247)		(71)		(1,357)
Net carrying amount	$	109	$	—	$	178	$	186	$	126	$	69	$	668


	Years Ended December 31,
(In millions)	2021		2020		2019
Emission allowances	$	24	$	28	$	32
Customer and supply contracts	66		12		14
Customer relationships	327		74		44
Marketing partnerships	24		24		15
Trade names	47		27		25
Other(a)	7		3		4
Total amortization	$	495	$	168	$	134

(a)For the years ended December 31, 2021, 2020 and 2019, other intangibles were amortized to depreciation and amortization expense for $3 million, $3 million and $4 million, respectively

The following table presents estimated amortization of NRG's intangible assets as of December 31, 2021 for each of the next five years:


(In millions)
Year Ended December 31,	Emission Allowances		Customer and Supply Contracts		Customer Relationships		Marketing Partnerships		Trade Names		Other		Total
2022	$	14	$	143	$	265	$	23	$	47	$	3	$	495
2023	12		120		216		23		46		4		421
2024	12		73		148		23		38		3		297
2025	11		50		110		22		32		4		229
2026	9		52		95		22		24		4		206

Intangible assets held-for-sale — From time to time, management may authorize the transfer from the Company's emission bank of emission allowances held-for-use to intangible assets held-for-sale. Emission allowances held-for-sale are included in other non-current assets on the Company's consolidated balance sheet and are not amortized, but rather expensed as sold. As of December 31, 2021 and 2020, the value of emission allowances held-for-sale was $15 million and $14 million, respectively, within the Corporate segment. Once transferred to held-for-sale, these emission allowances are prohibited from moving back to held-for-use.