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Pay vs Performance Disclosure - USD ($) | 12 Months Ended
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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

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