December 31, 2022	Gross Amount		Accumulated Amortization			Net Amount
Technologies & licenses		1,064		(795	)		269
Purchased & internally developed software		609		(514	)		95
Technologies in progress		41		—			41
Total		1,714		(1,309	)		405

December 31, 2021	Gross Amount		Accumulated Amortization			Net Amount
Technologies & licenses		1,050		(746	)		304
Purchased & internally developed software		567		(485	)		82
Technologies in progress		52		—			52
Total		1,669		(1,231	)		438

The line “Technologies in progress” in the table above also includes internally developed software under construction and software not ready for their intended use.

Amortization expense related to intangible assets subject to amortization was $103 million, $93 million and $79 million for the years ended December 31, 2022, 2021 and 2020, respectively.

Estimated future amortization expense related to intangible assets as of December 31, 2022 is as follows:

Year
2023			112
2024			98
2025			72
2026			42
2027			20
Thereafter			61
Total			405

In 2022, the Company recorded a $38 million impairment loss reported in the line “Research and development” of the consolidated statements of income. The impairment loss was related to certain technologies acquired as part of one of the Company’s recent business combinations.

In 2021 and 2020, the Company impaired $1 million and $4 million, respectively, of acquired licenses and technologies with no alternative future use.