Insider Trading Arrangements	3 Months Ended	12 Months Ended
Dec. 31, 2023 shares	Dec. 31, 2023 shares
Trading Arrangements, by Individual
Material Terms of Trading Arrangement		Paul Beswick, our Senior Vice President and Chief Information Officer, adopted a new trading plan on December 4, 2023. The plan’s maximum length is until December 3, 2024, and first trades will not occur until March 4, 2024, at the earliest. The trading plan is intended to permit Mr. Beswick to (1) sell 1,450 shares, (2) sell up to 8,510 shares subject to performance stock units (" PSUs") and (3) exercise and sell 5,000 stock options. •Dean Klisura, our President and Chief Executive Officer of Guy Carpenter and Vice Chair, Marsh McLennan, adopted a new trading plan on December 4, 2023. The plan’s maximum length is until December 3, 2024, and first trades will not occur until March 4, 2024, at the earliest. The trading plan is intended to permit Mr. Klisura to (1) sell up to 4,256 shares subject to PSUs, (2) sell 1,419 shares subject to restricted stock units ("RSUs") and (3) exercise and sell 9,994 stock options. •Mark McGivney, our Chief Financial Officer, adopted a new trading plan on December 4, 2023. The plan’s maximum length is until December 3, 2024, and first trades will not occur until March 4, 2024, at the earliest. The trading plan is intended to permit Mr. McGivney to (1) sell up to 25,526 shares subject to PSUs and (2) exercise and sell 66,393 stock options. •Stacy Mills, our Vice President and Controller, adopted a new trading plan on December 13, 2023. The plan’s maximum length is until December 12, 2024, and first trades will not occur until March 13, 2024, at the earliest. The trading plan is intended to permit Ms. Mills to (1) sell up to 1,702 shares subject to PSUs, (2) sell 1,572 shares subject to RSUs and (3) exercise and sell 4,101 stock options.
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Paul Beswick [Member]
Trading Arrangements, by Individual
Name	Paul Beswick
Title	Senior Vice President and Chief Information Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	December 4, 2023
Arrangement Duration	365 days
Dean Klisura [Member]
Trading Arrangements, by Individual
Name	Dean Klisura
Title	President and Chief Executive Officer of Guy Carpenter and Vice Chair, Marsh McLennan
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	December 4, 2023
Arrangement Duration	365 days
Mark McGivney [Member]
Trading Arrangements, by Individual
Name	Mark McGivney
Title	Chief Financial Officer
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	December 4, 2023
Arrangement Duration	365 days
Stacy Mills [Member]
Trading Arrangements, by Individual
Name	Stacy Mills
Title	Vice President and Controller
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	December 13, 2023
Arrangement Duration	365 days
Paul Beswick Rule Trading Arrangement, Shares [Member] \| Paul Beswick [Member]
Trading Arrangements, by Individual
Aggregate Available	1,450	1,450
Paul Beswick Trading Arrangement, Shares Subject To Performance Stock Units [Member] \| Paul Beswick [Member]
Trading Arrangements, by Individual
Aggregate Available	8,510	8,510
Paul Beswick Rule Trading Arrangement, Stock Options [Member] \| Paul Beswick [Member]
Trading Arrangements, by Individual
Aggregate Available	5,000	5,000
Dean Klisura Trading Arrangement, Shares Subject To Performance Stock Units [Member] \| Dean Klisura [Member]
Trading Arrangements, by Individual
Aggregate Available	4,256	4,256
Dean Klisura Rule Trading Arrangement, Restricted Stock Units [Member] \| Dean Klisura [Member]
Trading Arrangements, by Individual
Aggregate Available	1,419	1,419
Dean Klisura Rule Trading Arrangement, Stock Option [Member] \| Dean Klisura [Member]
Trading Arrangements, by Individual
Aggregate Available	9,994	9,994
Mark McGivney Trading Arrangement, Shares Subject To Performance Stock Units [Member] \| Mark McGivney [Member]
Trading Arrangements, by Individual
Aggregate Available	25,526	25,526
Mark McGivney Trading Arrangement, Stock Options [Member] \| Mark McGivney [Member]
Trading Arrangements, by Individual
Aggregate Available	66,393	66,393
Stacy Mills Trading Arrangement, Shares Subject To Performance Stock Units [Member] \| Stacy Mills [Member]
Trading Arrangements, by Individual
Aggregate Available	1,702	1,702
Stacy Mills Trading Arrangement, Shares Subject To Restricted Stock Units [Member] \| Stacy Mills [Member]
Trading Arrangements, by Individual
Aggregate Available	1,572	1,572
Stacy Mills Trading Arrangement, Stock Options [Member] \| Stacy Mills [Member]
Trading Arrangements, by Individual
Aggregate Available	4,101	4,101

Insider Trading Arrangements

3 Months Ended

12 Months Ended

Dec. 31, 2023

Paul Beswick, our Senior Vice President and Chief Information Officer, adopted a new trading plan on December 4, 2023. The plan’s maximum length is until December 3, 2024, and first trades will not occur until March 4, 2024, at the earliest. The trading plan is intended to permit Mr. Beswick to (1) sell 1,450 shares, (2) sell up to 8,510 shares subject to performance stock units (" PSUs") and (3) exercise and sell 5,000 stock options.

•Dean Klisura, our President and Chief Executive Officer of Guy Carpenter and Vice Chair, Marsh McLennan, adopted a new trading plan on December 4, 2023. The plan’s maximum length is until December 3, 2024, and first trades will not occur until March 4, 2024, at the earliest. The trading plan is intended to permit Mr. Klisura to (1) sell up to 4,256 shares subject to PSUs, (2) sell 1,419 shares subject to restricted stock units ("RSUs") and (3) exercise and sell 9,994 stock options.

•Mark McGivney, our Chief Financial Officer, adopted a new trading plan on December 4, 2023. The plan’s maximum length is until December 3, 2024, and first trades will not occur until March 4, 2024, at the earliest. The trading plan is intended to permit Mr. McGivney to (1) sell up to 25,526 shares subject to PSUs and (2) exercise and sell 66,393 stock options.

•Stacy Mills, our Vice President and Controller, adopted a new trading plan on December 13, 2023. The plan’s maximum length is until December 12, 2024, and first trades will not occur until March 13, 2024, at the earliest. The trading plan is intended to permit Ms. Mills to (1) sell up to 1,702 shares subject to PSUs, (2) sell 1,572 shares subject to RSUs and (3) exercise and sell 4,101 stock options.

Non-Rule 10b5-1 Arrangement Adopted

false

Rule 10b5-1 Arrangement Terminated

false

Non-Rule 10b5-1 Arrangement Terminated

false