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Pay vs Performance Disclosure | 12 Months Ended
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Dec. 31, 2022 USD ($) | Dec. 31, 2021 USD ($) | Dec. 31, 2020 USD ($)
Pay vs Performance Disclosure [Table] |  |  |
Pay vs Performance [Table Text Block] | Pay Versus Per f ormance As required by Item 402(v) of Regulation S-K, we are providing the following information regarding the relationship between executive “compensation actually paid” and the company’s financial performance for each of the last three completed calendar years. For further information concerning the company’s pay for performance philosophy and how the company aligns executive compensation with performance, see Overview of Our Executive Compensation Program and Components of Compensation for Named Executive Officers .
|  |  |  |  |  |  |  |  |  |  |  |  |  | Value of Initial Fixed $100 Investment Based On: |  |  |  |  |  |
Year |  | Summary Compensation Table Total for PEO (1) |  |  | Compensation Actually Paid to PEO (2) |  |  | Average Summary Compensation Table Total for Non-PEO Named Executive Officers (3) |  |  | Average Compensation Actually Paid to Non-PEO Named Executive Officers (4) |  |  | Total Shareholder Return (5) |  |  | Peer Group Total Shareholder Return (6) |  |  | Net Income (millions) |  |  | Adjusted EBITDAC Growth (7)
2022 |  | $ | 14,194,926 |  |  | $ | 23,190,737 |  |  | $ | 4,953,048 |  |  | $ | 6,908,560 |  |  | $ | 112.43 |  |  | $ | 97.54 |  |  | $ | 1,114.2 |  |  | 18.4%
2021 |  | $ | 13,882,255 |  |  | $ | 36,172,141 |  |  | $ | 5,079,153 |  |  | $ | 11,580,235 |  |  | $ | 139.01 |  |  | $ | 141.53 |  |  | $ | 906.8 |  |  | 17.2%
2020 |  | $ | 11,177,460 |  |  | $ | 26,471,099 |  |  | $ | 3,744,087 |  |  | $ | 8,713,871 |  |  | $ | 132.15 |  |  | $ | 106.24 |  |  | $ | 818.8 |  |  | 21.0%
(1) | The dollar amounts reported in this column are the amounts reported for Pat Gallagher (the company’s Chairman, President and Chief Executive Officer) for each of the corresponding years in the “Total” column of the 2022 Summary Compensation Table .
(2) | The dollar amounts reported in this column represent the amount of “compensation actually paid” to Pat Gallagher, as computed in accordance with Item 402(v) of Regulation S-K and do not reflect total compensation actually realized or received. In accordance with these rules, these amounts reflect “Total Compensation” as set forth in the 2022 Summary Compensation Table for each year, adjusted as shown below. Equity values are calculated in accordance with FASB ASC Topic 718, and the valuation assumptions used to calculate fair values did not materially differ from those disclosed at the time of grant.
Compensation Actually Paid to PEO |  | 2022 |  |  | 2021 |  |  | 2020 |
Summary Compensation Table Total |  | $ | 14,194,926 |  |  | $ | 13,882,255 |  |  | $ | 11,177,460 |
Less, value of “Stock Awards” and “Option Awards” reported in 2022 Summary Compensation Table |  | $ | 4,802,893 |  |  | $ | 5,492,149 |  |  | $ | 3,637,861 |
Less, Change in Pension Value reported in 2022 Summary Compensation Table |  |  | — |  |  | $ | 19,063 |  |  | $ | 98,106 |
Plus, year-end fair value of outstanding and unvested equity awards granted in the year |  | $ | 7,503,151 |  |  | $ | 13,095,137 |  |  | $ | 10,030,670 |
Plus, fair value as of vesting date of equity awards granted and vested in the year |  |  | — |  |  |  | — |  |  |  | — |
Plus (less), year over year change in fair value of outstanding and unvested equity awards granted in prior years |  | $ | 7,566,230 |  |  | $ | 14,263,150 |  |  | $ | 10,345,366 |
Plus (less), year over year change in fair value of equity awards granted in prior years that vested in the year |  | $ | (1,297,632 | ) |  | $ | 416,987 |  |  | $ | (1,371,701 | )
Plus, dividends or other earnings paid on awards in the covered fiscal year prior to vesting if not otherwise included in the Summary Compensation Table Total for the covered fiscal year |  | $ | 26,954 |  |  | $ | 25,824 |  |  | $ | 25,271 |
Less, prior year-end fair value for any equity awards forfeited in the year |  |  | — |  |  |  | — |  |  |  | — |
Plus, pension service cost for services rendered during the year |  |  | — |  |  |  | — |  |  |  | — |
Compensation Actually Paid to Pat Gallagher |  | $ | 23,190,737 |  |  | $ | 36,172,141 |  |  | $ | 26,471,099 |
(3) | The dollar amounts reported in this column represent the average of the amounts reported for the company’s named executive officers as a group (excluding Pat Gallagher) in the “Total” column of the 2022 Summary Compensation Table in each applicable year. The names of each of the named executive officers included for these purposes in each applicable year 2020 through 2022 are as follows: Doug Howell, Tom Gallagher, Scott Hudson and Walt Bay.
(4) | The dollar amounts reported in this column represent the average amount of “compensation actually paid” to the named executive officers as a group (excluding Pat Gallagher), as computed in accordance with Item 402(v) of Regulation S-K. In accordance with these rules, these amounts reflect “Total Compensation” as set forth in the 2022 Summary Compensation Table for each year, adjusted as shown below. Equity values are calculated in accordance with FASB ASC Topic 718, and the valuation assumptions used to calculate fair values did not materially differ from those disclosed at the time of the grant.
Average Compensation Actually Paid to Non-PEO Named Executive Officers |  | 2022 |  |  | 2021 |  |  | 2020 |
Summary Compensation Table Total |  | $ | 4,953,048 |  |  | $ | 5,079,153 |  |  | $ | 3,744,087 |
Less, value of “Stock Awards” and “Option Awards” reported in 2022 Summary Compensation Table |  | $ | 1,109,940 |  |  | $ | 1,322,515 |  |  | $ | 925,649 |
Less, Change in Pension Value reported in 2022 Summary Compensation Table |  |  | — |  |  | $ | 48 |  |  | $ | 20,737 |
Plus, year-end fair value of outstanding and unvested equity awards granted in the year |  | $ | 1,578,828 |  |  | $ | 2,958,220 |  |  | $ | 2,498,015 |
Plus, fair value as of vesting date of equity awards granted and vested in the year |  |  | — |  |  |  | — |  |  |  | — |
Plus (less), year over year change in fair value of outstanding and unvested equity awards granted in prior years |  | $ | 1,941,447 |  |  | $ | 4,681,938 |  |  | $ | 3,877,807 |
Plus (less), year over year change in fair value of equity awards granted in prior years that vested in the year |  | ($ | 462,939 | ) |  | $ | 174,571 |  |  | ($ | 467,652 | )
Plus, dividends or other earnings paid on awards in the covered fiscal year prior to vesting if not otherwise included in the Summary Compensation Table Total for the covered fiscal year |  | $ | 8,115 |  |  | $ | 8,916 |  |  | $ | 8,000 |
Less, prior year-end fair value for any equity awards forfeited in the year |  |  | — |  |  |  | — |  |  |  | — |
Plus, pension service cost for services rendered during the year |  |  | — |  |  |  | — |  |  |  | — |
Average Compensation Actually Paid to Non-PEO Named Executive Officers |  | $ | 6,908,560 |  |  | $ | 11,580,235 |  |  | $ | 8,713,871 |
(5) | Total Shareholder Return (TSR) is calculated by dividing (a) the sum of (i) the cumulative amount of dividends for the measurement period, assuming dividend reinvestment, and (ii) the difference between the company’s share price at the end of each fiscal year shown and the beginning of the measurement period, by (b) the company’s share price at the beginning of the measurement period. The beginning of the measurement period for each year in the table is December 31, 2019.
(6) | Includes Aon plc; Marsh & McLennan Companies, Inc.; Willis Towers Watson plc; and Brown & Brown, Inc.
(7) | “Adjusted EBITDAC” growth as defined for our annual cash incentives and PSUs under Annual Cash Incentives and Long-Term Incentives . See Exhibit B for reconciliations of non-GAAP measures.
Company Selected Measure Name | “Adjusted EBITDAC” growth |  |
Named Executive Officers, Footnote [Text Block] | The names of each of the named executive officers included for these purposes in each applicable year 2020 through 2022 are as follows: Doug Howell, Tom Gallagher, Scott Hudson and Walt Bay. |  |
Peer Group Issuers, Footnote [Text Block] | Includes Aon plc; Marsh & McLennan Companies, Inc.; Willis Towers Watson plc; and Brown & Brown, Inc. |  |
PEO Total Compensation Amount | $ 14,194,926 | $ 13,882,255 | $ 11,177,460
PEO Actually Paid Compensation Amount | $ 23,190,737 | 36,172,141 | 26,471,099
Adjustment To PEO Compensation, Footnote [Text Block] |
(2) | The dollar amounts reported in this column represent the amount of “compensation actually paid” to Pat Gallagher, as computed in accordance with Item 402(v) of Regulation S-K and do not reflect total compensation actually realized or received. In accordance with these rules, these amounts reflect “Total Compensation” as set forth in the 2022 Summary Compensation Table for each year, adjusted as shown below. Equity values are calculated in accordance with FASB ASC Topic 718, and the valuation assumptions used to calculate fair values did not materially differ from those disclosed at the time of grant.
Compensation Actually Paid to PEO |  | 2022 |  |  | 2021 |  |  | 2020 |
Summary Compensation Table Total |  | $ | 14,194,926 |  |  | $ | 13,882,255 |  |  | $ | 11,177,460 |
Less, value of “Stock Awards” and “Option Awards” reported in 2022 Summary Compensation Table |  | $ | 4,802,893 |  |  | $ | 5,492,149 |  |  | $ | 3,637,861 |
Less, Change in Pension Value reported in 2022 Summary Compensation Table |  |  | — |  |  | $ | 19,063 |  |  | $ | 98,106 |
Plus, year-end fair value of outstanding and unvested equity awards granted in the year |  | $ | 7,503,151 |  |  | $ | 13,095,137 |  |  | $ | 10,030,670 |
Plus, fair value as of vesting date of equity awards granted and vested in the year |  |  | — |  |  |  | — |  |  |  | — |
Plus (less), year over year change in fair value of outstanding and unvested equity awards granted in prior years |  | $ | 7,566,230 |  |  | $ | 14,263,150 |  |  | $ | 10,345,366 |
Plus (less), year over year change in fair value of equity awards granted in prior years that vested in the year |  | $ | (1,297,632 | ) |  | $ | 416,987 |  |  | $ | (1,371,701 | )
Plus, dividends or other earnings paid on awards in the covered fiscal year prior to vesting if not otherwise included in the Summary Compensation Table Total for the covered fiscal year |  | $ | 26,954 |  |  | $ | 25,824 |  |  | $ | 25,271 |
Less, prior year-end fair value for any equity awards forfeited in the year |  |  | — |  |  |  | — |  |  |  | — |
Plus, pension service cost for services rendered during the year |  |  | — |  |  |  | — |  |  |  | — |
Compensation Actually Paid to Pat Gallagher |  | $ | 23,190,737 |  |  | $ | 36,172,141 |  |  | $ | 26,471,099 |
Non-PEO NEO Average Total Compensation Amount | $ 4,953,048 | 5,079,153 | 3,744,087
Non-PEO NEO Average Compensation Actually Paid Amount | $ 6,908,560 | 11,580,235 | 8,713,871
Adjustment to Non-PEO NEO Compensation Footnote [Text Block] |
(4) | The dollar amounts reported in this column represent the average amount of “compensation actually paid” to the named executive officers as a group (excluding Pat Gallagher), as computed in accordance with Item 402(v) of Regulation S-K. In accordance with these rules, these amounts reflect “Total Compensation” as set forth in the 2022 Summary Compensation Table for each year, adjusted as shown below. Equity values are calculated in accordance with FASB ASC Topic 718, and the valuation assumptions used to calculate fair values did not materially differ from those disclosed at the time of the grant.
Average Compensation Actually Paid to Non-PEO Named Executive Officers |  | 2022 |  |  | 2021 |  |  | 2020 |
Summary Compensation Table Total |  | $ | 4,953,048 |  |  | $ | 5,079,153 |  |  | $ | 3,744,087 |
Less, value of “Stock Awards” and “Option Awards” reported in 2022 Summary Compensation Table |  | $ | 1,109,940 |  |  | $ | 1,322,515 |  |  | $ | 925,649 |
Less, Change in Pension Value reported in 2022 Summary Compensation Table |  |  | — |  |  | $ | 48 |  |  | $ | 20,737 |
Plus, year-end fair value of outstanding and unvested equity awards granted in the year |  | $ | 1,578,828 |  |  | $ | 2,958,220 |  |  | $ | 2,498,015 |
Plus, fair value as of vesting date of equity awards granted and vested in the year |  |  | — |  |  |  | — |  |  |  | — |
Plus (less), year over year change in fair value of outstanding and unvested equity awards granted in prior years |  | $ | 1,941,447 |  |  | $ | 4,681,938 |  |  | $ | 3,877,807 |
Plus (less), year over year change in fair value of equity awards granted in prior years that vested in the year |  | ($ | 462,939 | ) |  | $ | 174,571 |  |  | ($ | 467,652 | )
Plus, dividends or other earnings paid on awards in the covered fiscal year prior to vesting if not otherwise included in the Summary Compensation Table Total for the covered fiscal year |  | $ | 8,115 |  |  | $ | 8,916 |  |  | $ | 8,000 |
Less, prior year-end fair value for any equity awards forfeited in the year |  |  | — |  |  |  | — |  |  |  | — |
Plus, pension service cost for services rendered during the year |  |  | — |  |  |  | — |  |  |  | — |
Average Compensation Actually Paid to Non-PEO Named Executive Officers |  | $ | 6,908,560 |  |  | $ | 11,580,235 |  |  | $ | 8,713,871 |
Compensation Actually Paid vs. Total Shareholder Return [Text Block] | Compensation Actually Paid, Cumulative TSR and Peer Group TSR |  |
Compensation Actually Paid vs. Net Income [Text Block] | Compensation Actually Paid and Net Income |  |
Compensation Actually Paid vs. Company Selected Measure [Text Block] | Compensation Actually Paid and Adjusted EBITDAC |  |
Total Shareholder Return Vs Peer Group [Text Block] | Compensation Actually Paid, Cumulative TSR and Peer Group TSR |  |
Tabular List [Table Text Block] |
Most Important Measures in Determining NEO Pay
Adjusted EBITDAC growth
Adjusted Revenue growth
Adjusted EBITDAC per share growth
Total Shareholder Return Amount | $ 112.43 | 139.01 | 132.15
Peer Group Total Shareholder Return Amount | 97.54 | 141.53 | 106.24
Net Income (Loss) | $ 1,114,200,000 | $ 906,800,000 | $ 818,800,000
Company Selected Measure Amount | 18.4 | 17.2 | 21
PEO Name | Pat Gallagher |  |
Measure [Axis]: 1 |  |  |
Pay vs Performance Disclosure [Table] |  |  |
Measure Name | Adjusted EBITDAC growth |  |
Non-GAAP Measure Description [Text Block] | “Adjusted EBITDAC” growth as defined for our annual cash incentives and PSUs under Annual Cash Incentives and Long-Term Incentives . See Exhibit B for reconciliations of non-GAAP measures. |  |
Measure [Axis]: 2 |  |  |
Pay vs Performance Disclosure [Table] |  |  |
Measure Name | Adjusted Revenue growth |  |
Measure [Axis]: 3 |  |  |
Pay vs Performance Disclosure [Table] |  |  |
Measure Name | Adjusted EBITDAC per share growth |  |
PEO [Member] | Stock Awards [Member] |  |  |
Pay vs Performance Disclosure [Table] |  |  |
Adjustment to Compensation Amount | $ (4,802,893) | $ (5,492,149) | $ (3,637,861)
PEO [Member] | Change in Pension Value reported [Member] |  |  |
Pay vs Performance Disclosure [Table] |  |  |
Adjustment to Compensation Amount |  | (19,063) | (98,106)
PEO [Member] | year end fair value of outstanding and unvested equity awards granted in the year [Member] |  |  |
Pay vs Performance Disclosure [Table] |  |  |
Adjustment to Compensation Amount | 7,503,151 | 13,095,137 | 10,030,670
PEO [Member] | Year over year change in fair value of outstanding and unvested equity awards granted in prior years [Member] |  |  |
Pay vs Performance Disclosure [Table] |  |  |
Adjustment to Compensation Amount | 7,566,230 | 14,263,150 | 10,345,366
PEO [Member] | Year over year change in fair value of equity awards granted in prior years that vested in the year [Member] |  |  |
Pay vs Performance Disclosure [Table] |  |  |
Adjustment to Compensation Amount | (1,297,632) | 416,987 | (1,371,701)
PEO [Member] | Dividends or other earnings paid on awards in the covered fiscal year prior to vesting if not otherwise included in the Summary Compensation Table Total for the covered fiscal year [Member] |  |  |
Pay vs Performance Disclosure [Table] |  |  |
Adjustment to Compensation Amount | 26,954 | 25,824 | 25,271
Non-PEO NEO [Member] | Stock Awards [Member] |  |  |
Pay vs Performance Disclosure [Table] |  |  |
Adjustment to Compensation Amount | (1,109,940) | (1,322,515) | (925,649)
Non-PEO NEO [Member] | Change in Pension Value reported [Member] |  |  |
Pay vs Performance Disclosure [Table] |  |  |
Adjustment to Compensation Amount |  | (48) | (20,737)
Non-PEO NEO [Member] | year end fair value of outstanding and unvested equity awards granted in the year [Member] |  |  |
Pay vs Performance Disclosure [Table] |  |  |
Adjustment to Compensation Amount | 1,578,828 | 2,958,220 | 2,498,015
Non-PEO NEO [Member] | Year over year change in fair value of outstanding and unvested equity awards granted in prior years [Member] |  |  |
Pay vs Performance Disclosure [Table] |  |  |
Adjustment to Compensation Amount | 1,941,447 | 4,681,938 | 3,877,807
Non-PEO NEO [Member] | Year over year change in fair value of equity awards granted in prior years that vested in the year [Member] |  |  |
Pay vs Performance Disclosure [Table] |  |  |
Adjustment to Compensation Amount | (462,939) | 174,571 | (467,652)
Non-PEO NEO [Member] | Dividends or other earnings paid on awards in the covered fiscal year prior to vesting if not otherwise included in the Summary Compensation Table Total for the covered fiscal year [Member] |  |  |
Pay vs Performance Disclosure [Table] |  |  |
Adjustment to Compensation Amount | $ 8,115 | $ 8,916 | $ 8,000

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