During 2019, the Company retained industry-recognized experts in supply chain optimization and organizational excellence to assist in a comprehensive financial and operational review which was focused on product cost and gross margin improvement, and general and administrative expenses simplification. Certain restructuring actions have been implemented under this program as well as previous programs. Product & Solutions segment restructuring expenses for the years ended December 31, 2020, 2019, and 2018 were $19 million, $26 million, and $5 million, respectively. ADI Global Distribution segment restructuring expenses for the years ended December 31, 2020, 2019, and 2018 were $6 million, $4 million, and $0 million, respectively. Corporate restructuring expenses for the years ended December 31, 2020, 2019 and 2018 were $15 million, $7 million, and $0 million, respectively. Restructuring expenses for all periods are primarily related to severance.

The Company’s restructuring expenses for the years ended December 31, 2020, 2019 and 2018 are as follows:

	Years Ended December 31,
	2020		2019		2018
Cost of goods sold	$	9	$	13	$	4
Selling, general and administrative expenses		31		24		1
	$	40	$	37	$	5

The following table summarizes the status of total restructuring reserves related to severance cost included in Accrued liabilities in the Consolidated Balance Sheets:

	Years Ended December 31,
	2020			2019			2018
Beginning of year	$	19		$	13		$	22
Charges		40			38			5
Usage		(35	)		(31	)		(9	)
Other		-			(1	)		(5	)
End of year	$	24		$	19		$	13