Pay vs Performance Disclosure - USD ($)

12 Months Ended

Dec. 31, 2023

Dec. 31, 2022

Dec. 31, 2021

Dec. 31, 2020

Pay vs Performance Disclosure

Pay vs Performance Disclosure, Table

			Average
			Summary
	Summary		Compensation	Average	Value of Initial Fixed $100
	Compensation		Table	Compensation	Investment Based on:
	Table	Compensation	Total for	Actually Paid to	West Total	Peer Group Total
	Total for	Actually Paid to	Non-PEO	Non-PEO	Shareholder	Shareholder	Net Income	Revenue
Year	PEO ($)(1)	PEO ($)(1,2,3)	NEOs ($)(1)	NEOs ($)(1,2,3)	Return ($)	Return ($)(4)	(GAAP)($MM)	($MM) (5)
2023	9,395,896	16,987,422	2,082,653	3,165,717	125	126	593	2,950
2022	7,905,061	(12,073,257)	1,772,404	(632,515)	83	124	586	2,887
2021	9,472,757	35,095,275	1,998,585	5,071,519	166	126	662	2,832
2020	7,642,296	30,515,658	1,873,373	5,653,613	100	100	346	2,147

(1) For each year represented, our PEO and NEOs were as follows:

Officer	2023	2022	2021	2020
PEO	Eric Green	Eric Green	Eric Green	Eric Green
NEO	Bernard J. Birkett	Bernard J. Birkett	Bernard J. Birkett	Bernard J. Birkett
NEO	Silji Abraham	Silji Abraham	Silji Abraham	Silji Abraham
NEO	Kimberly B. MacKay	Kimberly B. MacKay	David Montecalvo	David Montecalvo
NEO	Cindy Reiss-Clark	Cindy Reiss-Clark	Kimberly B. MacKay	George Miller

(2) Amounts shown for Compensation “Actually Paid” are computed in accordance with Item 402(v) and do not reflect the actual amount of compensation earned by or paid to the NEOs during the applicable year. These amounts reflect total compensation as reported in the Summary Compensation Table with certain adjustments as described in footnote (3) below.

(3) Compensation “Actually Paid” reflects the exclusions and inclusions of equity awards for the PEO and the other NEOs as set forth below and calculated in accordance with FASB ASC Topic 718. The valuation methodologies and assumptions used to calculate Compensation “Actually Paid” are based on our grant date fair value of these awards as disclosed in the company’s audited financial statements for the years reflected in the table below.

Summary Compensation Table Total to Compensation “Actually Paid”

Reconciliation for the PEO and Non-PEO NEOs

	Calculation for PEO				Calculation for Average of Non-PEO NEOs
Calculation(1) of Compensation “Actually Paid”	2020 ($)	2021 ($)	2022 ($)	2023 ($)	2020 ($)	2021 ($)	2022 ($)	2023 ($)
SCT Total Compensation	7,642,296	9,472,757	7,905,061	9,395,896	1,873,373	1,998,585	1,772,404	2,082,653
Less: Stock and Option Award Values Reported in SCT for the Covered Year	(4,500,154)	(5,500,108)	(6,000,281)	(6,500,268)	(799,992)	(762,613)	(987,595)	(1,062,670)
Plus: Fair Value for Stock and Option Awards Granted in the Covered Year	10,107,843	12,288,155	4,429,188	7,670,988	1,833,089	1,509,999	734,313	1,254,057
Change in Fair Value of Outstanding Unvested Stock and Option Awards from Prior Years	16,240,432	19,186,892	(13,183,737)	3,050,648	2,609,379	2,238,405	(1,598,040)	416,668
Change in Fair Value of Stock and Options Awards from Prior Years that Vested in the Covered year	979,621	(346,776)	(5,103,659)	3,370,158	137,764	87,143	(553,597)	475,009
Less: Aggregate Change in Actuarial Present Value of Pension Benefits	45,620	(5,645)	(119,829)	—	—	—	—	—
Compensation “Actually Paid”	30,515,658	35,095,275	(12,073,257)	16,987,422	5,653,613	5,071,519	(632,515)	3,165,717

(1) For the PEO and other NEOs, for each covered year, service cost and prior service cost of pension benefits equals $0, fair value of awards that are granted and vest in the same covered fiscal year equals $0, and fair value of awards granted in prior years that are determined to fail to meet the applicable vesting conditions during the covered fiscal year equals $0.

Equity Valuations: Stock option grant date fair values are calculated based on the Black-Scholes option pricing model as of date of grant. Adjustments have been made using stock option fair values as of each measurement date using the stock price as of the measurement date and updated assumptions (i.e., term, volatility, dividend yield, risk free rates) as of the measurement date. Performance-based restricted share unit grant date fair values are calculated using the stock price as of date of grant assuming target performance. Adjustments have been made using the stock price and performance accrual modifier as of year-end and as of the date of vest. Time-based restricted share unit grant date fair values are calculated using the stock price as of date of grant. Adjustments have been made using the stock price as of year-end and as of each vesting date in accordance with Item 402(v). The aggregate change in actuarial present value of accumulated benefit under pension plans reflects the amount reported for the applicable year in the SCT.

(4) Reflects total shareholder return indexed to $100 per share for West and the S&P 500 Health Care Index (“Peer Group”), which is the industry line peer group reported in our 2023 Form 10-K. For each reporting year, TSR is measured as follows:

Reporting Year	Beginning	End	Number of Years
2023	1/2/2020	12/31/2023	4
2022	1/2/2020	12/31/2022	3
2021	1/2/2020	12/31/2021	2
2020	1/2/2020	12/31/2020	1

(5) Pursuant to Item 402(v), we determined West’s revenue to be the most important financial performance measure used to link Company performance to Compensation “Actually Paid” to our PEO and other NEOs, and this is designated as our Company-Selected Measure for 2023. This performance measure may not have been the most important financial performance measure for years 2020 through 2022, and we may determine a different financial performance measure to be the most important such measure in future years.

Company Selected Measure Name

Revenue

Named Executive Officers, Footnote

(1) For each year represented, our PEO and NEOs were as follows:

Officer	2023	2022	2021	2020
PEO	Eric Green	Eric Green	Eric Green	Eric Green
NEO	Bernard J. Birkett	Bernard J. Birkett	Bernard J. Birkett	Bernard J. Birkett
NEO	Silji Abraham	Silji Abraham	Silji Abraham	Silji Abraham
NEO	Kimberly B. MacKay	Kimberly B. MacKay	David Montecalvo	David Montecalvo
NEO	Cindy Reiss-Clark	Cindy Reiss-Clark	Kimberly B. MacKay	George Miller

Peer Group Issuers, Footnote

(4) Reflects total shareholder return indexed to $100 per share for West and the S&P 500 Health Care Index (“Peer Group”), which is the industry line peer group reported in our 2023 Form 10-K. For each reporting year, TSR is measured as follows:

Reporting Year	Beginning	End	Number of Years
2023	1/2/2020	12/31/2023	4
2022	1/2/2020	12/31/2022	3
2021	1/2/2020	12/31/2021	2
2020	1/2/2020	12/31/2020	1

PEO Total Compensation Amount

$ 9,395,896

$ 7,905,061

$ 9,472,757

$ 7,642,296

PEO Actually Paid Compensation Amount

$ 16,987,422

(12,073,257)

35,095,275

30,515,658

Adjustment To PEO Compensation, Footnote

(3) Compensation “Actually Paid” reflects the exclusions and inclusions of equity awards for the PEO and the other NEOs as set forth below and calculated in accordance with FASB ASC Topic 718. The valuation methodologies and assumptions used to calculate Compensation “Actually Paid” are based on our grant date fair value of these awards as disclosed in the company’s audited financial statements for the years reflected in the table below.

Summary Compensation Table Total to Compensation “Actually Paid”

Reconciliation for the PEO and Non-PEO NEOs

	Calculation for PEO				Calculation for Average of Non-PEO NEOs
Calculation(1) of Compensation “Actually Paid”	2020 ($)	2021 ($)	2022 ($)	2023 ($)	2020 ($)	2021 ($)	2022 ($)	2023 ($)
SCT Total Compensation	7,642,296	9,472,757	7,905,061	9,395,896	1,873,373	1,998,585	1,772,404	2,082,653
Less: Stock and Option Award Values Reported in SCT for the Covered Year	(4,500,154)	(5,500,108)	(6,000,281)	(6,500,268)	(799,992)	(762,613)	(987,595)	(1,062,670)
Plus: Fair Value for Stock and Option Awards Granted in the Covered Year	10,107,843	12,288,155	4,429,188	7,670,988	1,833,089	1,509,999	734,313	1,254,057
Change in Fair Value of Outstanding Unvested Stock and Option Awards from Prior Years	16,240,432	19,186,892	(13,183,737)	3,050,648	2,609,379	2,238,405	(1,598,040)	416,668
Change in Fair Value of Stock and Options Awards from Prior Years that Vested in the Covered year	979,621	(346,776)	(5,103,659)	3,370,158	137,764	87,143	(553,597)	475,009
Less: Aggregate Change in Actuarial Present Value of Pension Benefits	45,620	(5,645)	(119,829)	—	—	—	—	—
Compensation “Actually Paid”	30,515,658	35,095,275	(12,073,257)	16,987,422	5,653,613	5,071,519	(632,515)	3,165,717

(1) For the PEO and other NEOs, for each covered year, service cost and prior service cost of pension benefits equals $0, fair value of awards that are granted and vest in the same covered fiscal year equals $0, and fair value of awards granted in prior years that are determined to fail to meet the applicable vesting conditions during the covered fiscal year equals $0.

Non-PEO NEO Average Total Compensation Amount

$ 2,082,653

1,772,404

1,998,585

1,873,373

Non-PEO NEO Average Compensation Actually Paid Amount

$ 3,165,717

(632,515)

5,071,519

5,653,613

Adjustment to Non-PEO NEO Compensation Footnote

(3) Compensation “Actually Paid” reflects the exclusions and inclusions of equity awards for the PEO and the other NEOs as set forth below and calculated in accordance with FASB ASC Topic 718. The valuation methodologies and assumptions used to calculate Compensation “Actually Paid” are based on our grant date fair value of these awards as disclosed in the company’s audited financial statements for the years reflected in the table below.

Summary Compensation Table Total to Compensation “Actually Paid”

Reconciliation for the PEO and Non-PEO NEOs

	Calculation for PEO				Calculation for Average of Non-PEO NEOs
Calculation(1) of Compensation “Actually Paid”	2020 ($)	2021 ($)	2022 ($)	2023 ($)	2020 ($)	2021 ($)	2022 ($)	2023 ($)
SCT Total Compensation	7,642,296	9,472,757	7,905,061	9,395,896	1,873,373	1,998,585	1,772,404	2,082,653
Less: Stock and Option Award Values Reported in SCT for the Covered Year	(4,500,154)	(5,500,108)	(6,000,281)	(6,500,268)	(799,992)	(762,613)	(987,595)	(1,062,670)
Plus: Fair Value for Stock and Option Awards Granted in the Covered Year	10,107,843	12,288,155	4,429,188	7,670,988	1,833,089	1,509,999	734,313	1,254,057
Change in Fair Value of Outstanding Unvested Stock and Option Awards from Prior Years	16,240,432	19,186,892	(13,183,737)	3,050,648	2,609,379	2,238,405	(1,598,040)	416,668
Change in Fair Value of Stock and Options Awards from Prior Years that Vested in the Covered year	979,621	(346,776)	(5,103,659)	3,370,158	137,764	87,143	(553,597)	475,009
Less: Aggregate Change in Actuarial Present Value of Pension Benefits	45,620	(5,645)	(119,829)	—	—	—	—	—
Compensation “Actually Paid”	30,515,658	35,095,275	(12,073,257)	16,987,422	5,653,613	5,071,519	(632,515)	3,165,717

(1) For the PEO and other NEOs, for each covered year, service cost and prior service cost of pension benefits equals $0, fair value of awards that are granted and vest in the same covered fiscal year equals $0, and fair value of awards granted in prior years that are determined to fail to meet the applicable vesting conditions during the covered fiscal year equals $0.

Equity Valuation Assumption Difference, Footnote

Equity Valuations: Stock option grant date fair values are calculated based on the Black-Scholes option pricing model as of date of grant. Adjustments have been made using stock option fair values as of each measurement date using the stock price as of the measurement date and updated assumptions (i.e., term, volatility, dividend yield, risk free rates) as of the measurement date. Performance-based restricted share unit grant date fair values are calculated using the stock price as of date of grant assuming target performance. Adjustments have been made using the stock price and performance accrual modifier as of year-end and as of the date of vest. Time-based restricted share unit grant date fair values are calculated using the stock price as of date of grant. Adjustments have been made using the stock price as of year-end and as of each vesting date in accordance with Item 402(v). The aggregate change in actuarial present value of accumulated benefit under pension plans reflects the amount reported for the applicable year in the SCT.

Compensation Actually Paid vs. Total Shareholder Return

     

Compensation Actually Paid vs. Net Income

     

Compensation Actually Paid vs. Company Selected Measure

     

Total Shareholder Return Vs Peer Group

     

Tabular List, Table

Listed below are the financial and non-financial performance measures which in our assessment represent the most important performance measures we used during 2023 to link Compensation “Actually Paid” to our PEO and other NEOs to company performance.

Most Important Performance Measures

Earnings per Share

Revenue

Operating Cash Flow

Consolidated Gross Profit

Sales Compounded Annual Growth Rate

Return on Invested Capital

Total Shareholder Return Amount

$ 125

83

166

100

Peer Group Total Shareholder Return Amount

126

124

126

100

Net Income (Loss)

$ 593,000,000

$ 586,000,000

$ 662,000,000

$ 346,000,000

Company Selected Measure Amount

2,950,000,000

2,887,000,000

2,832,000,000

2,147,000,000

PEO Name

Eric Green

Measure:: 1

Pay vs Performance Disclosure

Name

Earnings per Share

Measure:: 2

Pay vs Performance Disclosure

Name

Revenue

Non-GAAP Measure Description

(5) Pursuant to Item 402(v), we determined West’s revenue to be the most important financial performance measure used to link Company performance to Compensation “Actually Paid” to our PEO and other NEOs, and this is designated as our Company-Selected Measure for 2023. This performance measure may not have been the most important financial performance measure for years 2020 through 2022, and we may determine a different financial performance measure to be the most important such measure in future years.

Measure:: 3

Pay vs Performance Disclosure

Name

Operating Cash Flow

Measure:: 4

Pay vs Performance Disclosure

Name

Consolidated Gross Profit

Measure:: 5

Pay vs Performance Disclosure

Name

Sales Compounded Annual Growth Rate

Measure:: 6

Pay vs Performance Disclosure

Name

Return on Invested Capital

Service Cost and Prior Service Cost of Pension Benefits

Pay vs Performance Disclosure

Adjustment to Compensation, Amount

$ 0

$ 0

$ 0

$ 0

Fair Value of Awards Granted and Vest

Pay vs Performance Disclosure

Adjustment to Compensation, Amount

0

0

0

0

Fair Value of Awards Granted that are Determined to Fail to Meet the Applicable Vesting Conditions

Pay vs Performance Disclosure

Adjustment to Compensation, Amount

0

0

0

0

PEO | Less: Stock and Option Award Values Reported in SCT for the Covered Year

Pay vs Performance Disclosure

Adjustment to Compensation, Amount

(6,500,268)

(6,000,281)

(5,500,108)

(4,500,154)

PEO | Plus: Fair Value for Stock and Option Awards Granted in the Covered Year

Pay vs Performance Disclosure

Adjustment to Compensation, Amount

7,670,988

4,429,188

12,288,155

10,107,843

PEO | Change in Fair Value of Outstanding Unvested Stock and Option Awards from Prior Years

Pay vs Performance Disclosure

Adjustment to Compensation, Amount

3,050,648

(13,183,737)

19,186,892

16,240,432

PEO | Change in Fair Value of Stock and Options Awards from Prior Years that Vested in the Covered year

Pay vs Performance Disclosure

Adjustment to Compensation, Amount

3,370,158

(5,103,659)

(346,776)

979,621

PEO | Less: Aggregate Change in Actuarial Present Value of Pension Benefits

Pay vs Performance Disclosure

Adjustment to Compensation, Amount

(119,829)

(5,645)

45,620

Non-PEO NEO | Less: Stock and Option Award Values Reported in SCT for the Covered Year

Pay vs Performance Disclosure

Adjustment to Compensation, Amount

(1,062,670)

(987,595)

(762,613)

(799,992)

Non-PEO NEO | Plus: Fair Value for Stock and Option Awards Granted in the Covered Year

Pay vs Performance Disclosure

Adjustment to Compensation, Amount

1,254,057

734,313

1,509,999

1,833,089

Non-PEO NEO | Change in Fair Value of Outstanding Unvested Stock and Option Awards from Prior Years

Pay vs Performance Disclosure

Adjustment to Compensation, Amount

416,668

(1,598,040)

2,238,405

2,609,379

Non-PEO NEO | Change in Fair Value of Stock and Options Awards from Prior Years that Vested in the Covered year

Pay vs Performance Disclosure

Adjustment to Compensation, Amount

$ 475,009

$ (553,597)

$ 87,143

$ 137,764