The changes in the carrying amount of goodwill for the years ended December 31, 2022 and 2021 are as follows (in millions):

Balance, beginning balance	2022			2021
Goodwill	$	7,033		$	7,033
Accumulated impairment losses		(2,814	)		(2,814	)
		4,219			4,219
Goodwill acquired as part of acquisitions during current year		11			5
Goodwill allocated to hospitals divested or held-for-sale		(64	)		(5	)

Balance, end of year
Goodwill		6,980			7,033
Accumulated impairment losses		(2,814	)		(2,814	)
	$	4,166		$	4,219

Goodwill is allocated to each identified reporting unit, which is defined as an operating segment or one level below the operating segment (referred to as a component of the entity). Management has determined that the Company’s operating segment meets the criteria to be classified as a reporting unit. At December 31, 2022, after giving effect to the 2022 acquisition and divestiture activity, the Company had approximately $4.2 billion of goodwill recorded.

Goodwill is evaluated for impairment annually and when an event occurs or circumstances change that, more likely than not, reduce the fair value of the reporting unit below its carrying value. The Company performed its last annual goodwill impairment evaluation during the fourth quarter of 2022 using an October 31, 2022 measurement date, which indicated no impairment.

The Company estimates the fair value of the reporting unit using both a discounted cash flow model as well as a market multiple model. The cash flow forecasts are adjusted by an appropriate discount rate based on the Company’s estimate of a market participant’s weighted-average cost of capital. These models are both based on the Company’s best estimate of future revenues and operating costs and are reconciled to the Company’s consolidated market capitalization, with consideration of the amount a potential acquirer would be required to pay, in the form of a control premium, in order to gain sufficient ownership to set policies, direct operations and control management decisions.

The determination of fair value in the Company’s goodwill impairment analysis is based on an estimate of fair value for the reporting unit utilizing known and estimated inputs at the evaluation date. Some of those inputs include, but are not limited to, the most recent price of the Company’s common stock and fair value of long-term debt, the Company’s recent financial results, estimates of future revenue and expense growth, estimated market multiples, expected capital expenditures, income tax rates, costs of invested capital and a discount rate.

Future estimates of fair value could be adversely affected if the actual outcome of one or more of the assumptions described above changes materially in the future, including as a result of any decline in the Company’s stock price and the fair value of its long-term debt, an increase in the volatility of the Company’s stock price and the fair value of its long-term debt, lower-than-expected hospital volumes and/or net operating revenues, higher market interest rates, increased operating costs or other adverse impacts on the Company’s financial results. Such changes impacting the calculation of fair value could result in a material impairment charge in the future.

The determination of fair value of the Company’s hospital operations reporting unit as part of its goodwill impairment measurement represents a Level 3 fair value measurement in the fair value hierarchy due to its use of internal projections and unobservable measurement inputs.

No intangible assets other than goodwill were acquired during the years ended December 31, 2022 and 2021. The gross carrying amount of the Company’s other intangible assets subject to amortization was $4 million and $1 million at December 31, 2022 and 2021, respectively, and the net carrying amount was $2 million and less than $1 million at December 31, 2022 and 2021, respectively. The carrying amount of the Company’s other intangible assets not subject to amortization was $50 million and $54 million at December 31, 2022 and 2021, respectively. Other intangible assets are included in other assets, net on the Company’s consolidated balance sheets. Substantially all of the Company’s intangible assets are contract-based intangible assets related to operating licenses, management contracts, or non-compete agreements entered into in connection with prior acquisitions.

The weighted-average remaining amortization period for the intangible assets subject to amortization is approximately three years. There are no expected residual values related to these intangible assets. Amortization expense on these intangible assets was $1 million during the year ended December 31, 2022, and less than $1 million during both of the years ended December 31, 2021 and 2020. Amortization expense on intangible assets is estimated to be less than $1 million in 2023, 2024 and 2025.

The gross carrying amount of capitalized software for internal use was approximately $968 million and $992 million at December 31, 2022 and 2021, respectively, and the net carrying amount was approximately $170 million and $215 million at December 31, 2022 and 2021, respectively. The estimated amortization period for capitalized internal-use software is generally three years. There is no expected residual value for capitalized internal-use software. At December 31, 2022, there were approximately $82 million of capitalized costs for internal-use software that is currently in the development stage and will begin amortization once the software project is complete and ready for its intended use. Amortization expense on capitalized internal-use software was $85 million, $108 million and $123 million during the years ended December 31, 2022, 2021 and 2020, respectively. Amortization expense on capitalized internal-use software is estimated to be $66 million in 2023, $43 million in 2024, $26 million in 2025, $20 million in 2026, $8 million in 2027 and $7 million thereafter.