{"cik":62709,"taxonomy":"us-gaap","tag":"ShareBasedCompensation","label":"Share-based Payment Arrangement, Noncash Expense","description":"Amount of noncash expense for share-based payment arrangement.","entityName":"MARSH & MCLENNAN COMPANIES, INC.","units":{"USD":[{"start":"2012-01-01","end":"2012-12-31","val":177000000,"accn":"0000062709-15-000005","fy":2014,"fp":"FY","form":"10-K","filed":"2015-02-26","frame":"CY2012"},{"start":"2013-01-01","end":"2013-12-31","val":129000000,"accn":"0000062709-15-000005","fy":2014,"fp":"FY","form":"10-K","filed":"2015-02-26"},{"start":"2013-01-01","end":"2013-12-31","val":129000000,"accn":"0000062709-16-000040","fy":2015,"fp":"FY","form":"10-K","filed":"2016-02-24","frame":"CY2013"},{"start":"2014-01-01","end":"2014-12-31","val":93000000,"accn":"0000062709-15-000005","fy":2014,"fp":"FY","form":"10-K","filed":"2015-02-26"},{"start":"2014-01-01","end":"2014-12-31","val":93000000,"accn":"0000062709-16-000040","fy":2015,"fp":"FY","form":"10-K","filed":"2016-02-24"},{"start":"2014-01-01","end":"2014-12-31","val":93000000,"accn":"0000062709-17-000008","fy":2016,"fp":"FY","form":"10-K","filed":"2017-02-24","frame":"CY2014"},{"start":"2015-01-01","end":"2015-12-31","val":88000000,"accn":"0000062709-16-000040","fy":2015,"fp":"FY","form":"10-K","filed":"2016-02-24"},{"start":"2015-01-01","end":"2015-12-31","val":88000000,"accn":"0000062709-17-000008","fy":2016,"fp":"FY","form":"10-K","filed":"2017-02-24"},{"start":"2015-01-01","end":"2015-12-31","val":88000000,"accn":"0000062709-18-000007","fy":2017,"fp":"FY","form":"10-K","filed":"2018-02-22"},{"start":"2015-01-01","end":"2015-12-31","val":88000000,"accn":"0000062709-18-000020","fy":2017,"fp":"FY","form":"8-K","filed":"2018-05-09","frame":"CY2015"},{"start":"2016-01-01","end":"2016-12-31","val":109000000,"accn":"0000062709-17-000008","fy":2016,"fp":"FY","form":"10-K","filed":"2017-02-24"},{"start":"2016-01-01","end":"2016-12-31","val":109000000,"accn":"0000062709-18-000007","fy":2017,"fp":"FY","form":"10-K","filed":"2018-02-22"},{"start":"2016-01-01","end":"2016-12-31","val":109000000,"accn":"0000062709-18-000020","fy":2017,"fp":"FY","form":"8-K","filed":"2018-05-09"},{"start":"2016-01-01","end":"2016-12-31","val":109000000,"accn":"0000062709-19-000010","fy":2018,"fp":"FY","form":"10-K","filed":"2019-02-21","frame":"CY2016"},{"start":"2017-01-01","end":"2017-12-31","val":149000000,"accn":"0000062709-18-000007","fy":2017,"fp":"FY","form":"10-K","filed":"2018-02-22"},{"start":"2017-01-01","end":"2017-12-31","val":149000000,"accn":"0000062709-18-000020","fy":2017,"fp":"FY","form":"8-K","filed":"2018-05-09"},{"start":"2017-01-01","end":"2017-12-31","val":149000000,"accn":"0000062709-19-000010","fy":2018,"fp":"FY","form":"10-K","filed":"2019-02-21"},{"start":"2017-01-01","end":"2017-12-31","val":149000000,"accn":"0000062709-20-000010","fy":2019,"fp":"FY","form":"10-K","filed":"2020-02-20","frame":"CY2017"},{"start":"2018-01-01","end":"2018-06-30","val":99000000,"accn":"0000062709-19-000037","fy":2019,"fp":"Q2","form":"10-Q","filed":"2019-08-02"},{"start":"2018-01-01","end":"2018-09-30","val":146000000,"accn":"0000062709-19-000043","fy":2019,"fp":"Q3","form":"10-Q","filed":"2019-10-30"},{"start":"2018-01-01","end":"2018-12-31","val":193000000,"accn":"0000062709-19-000010","fy":2018,"fp":"FY","form":"10-K","filed":"2019-02-21"},{"start":"2018-01-01","end":"2018-12-31","val":193000000,"accn":"0000062709-20-000010","fy":2019,"fp":"FY","form":"10-K","filed":"2020-02-20"},{"start":"2018-01-01","end":"2018-12-31","val":193000000,"accn":"0000062709-21-000008","fy":2020,"fp":"FY","form":"10-K","filed":"2021-02-17","frame":"CY2018"},{"start":"2019-01-01","end":"2019-03-31","val":57000000,"accn":"0000062709-20-000024","fy":2020,"fp":"Q1","form":"10-Q","filed":"2020-05-01","frame":"CY2019Q1"},{"start":"2019-01-01","end":"2019-06-30","val":117000000,"accn":"0000062709-19-000037","fy":2019,"fp":"Q2","form":"10-Q","filed":"2019-08-02"},{"start":"2019-01-01","end":"2019-06-30","val":117000000,"accn":"0000062709-20-000043","fy":2020,"fp":"Q2","form":"10-Q","filed":"2020-07-31"},{"start":"2019-01-01","end":"2019-09-30","val":184000000,"accn":"0000062709-19-000043","fy":2019,"fp":"Q3","form":"10-Q","filed":"2019-10-30"},{"start":"2019-01-01","end":"2019-09-30","val":184000000,"accn":"0000062709-20-000053","fy":2020,"fp":"Q3","form":"10-Q","filed":"2020-10-30"},{"start":"2019-01-01","end":"2019-12-31","val":252000000,"accn":"0000062709-20-000010","fy":2019,"fp":"FY","form":"10-K","filed":"2020-02-20"},{"start":"2019-01-01","end":"2019-12-31","val":252000000,"accn":"0000062709-21-000008","fy":2020,"fp":"FY","form":"10-K","filed":"2021-02-17"},{"start":"2019-01-01","end":"2019-12-31","val":252000000,"accn":"0000062709-22-000009","fy":2021,"fp":"FY","form":"10-K","filed":"2022-02-16","frame":"CY2019"},{"start":"2020-01-01","end":"2020-03-31","val":72000000,"accn":"0000062709-20-000024","fy":2020,"fp":"Q1","form":"10-Q","filed":"2020-05-01"},{"start":"2020-01-01","end":"2020-03-31","val":72000000,"accn":"0000062709-21-000015","fy":2021,"fp":"Q1","form":"10-Q","filed":"2021-04-27","frame":"CY2020Q1"},{"start":"2020-01-01","end":"2020-06-30","val":147000000,"accn":"0000062709-20-000043","fy":2020,"fp":"Q2","form":"10-Q","filed":"2020-07-31"},{"start":"2020-01-01","end":"2020-06-30","val":147000000,"accn":"0000062709-21-000038","fy":2021,"fp":"Q2","form":"10-Q","filed":"2021-07-22"},{"start":"2020-01-01","end":"2020-09-30","val":219000000,"accn":"0000062709-20-000053","fy":2020,"fp":"Q3","form":"10-Q","filed":"2020-10-30"},{"start":"2020-01-01","end":"2020-09-30","val":219000000,"accn":"0000062709-21-000047","fy":2021,"fp":"Q3","form":"10-Q","filed":"2021-10-21"},{"start":"2020-01-01","end":"2020-12-31","val":290000000,"accn":"0000062709-21-000008","fy":2020,"fp":"FY","form":"10-K","filed":"2021-02-17"},{"start":"2020-01-01","end":"2020-12-31","val":290000000,"accn":"0000062709-22-000009","fy":2021,"fp":"FY","form":"10-K","filed":"2022-02-16"},{"start":"2020-01-01","end":"2020-12-31","val":290000000,"accn":"0000062709-23-000014","fy":2022,"fp":"FY","form":"10-K","filed":"2023-02-13","frame":"CY2020"},{"start":"2021-01-01","end":"2021-03-31","val":78000000,"accn":"0000062709-21-000015","fy":2021,"fp":"Q1","form":"10-Q","filed":"2021-04-27"},{"start":"2021-01-01","end":"2021-03-31","val":78000000,"accn":"0000062709-22-000025","fy":2022,"fp":"Q1","form":"10-Q","filed":"2022-04-21","frame":"CY2021Q1"},{"start":"2021-01-01","end":"2021-06-30","val":176000000,"accn":"0000062709-21-000038","fy":2021,"fp":"Q2","form":"10-Q","filed":"2021-07-22"},{"start":"2021-01-01","end":"2021-06-30","val":176000000,"accn":"0000062709-22-000066","fy":2022,"fp":"Q2","form":"10-Q","filed":"2022-07-21"},{"start":"2021-01-01","end":"2021-09-30","val":263000000,"accn":"0000062709-21-000047","fy":2021,"fp":"Q3","form":"10-Q","filed":"2021-10-21"},{"start":"2021-01-01","end":"2021-09-30","val":263000000,"accn":"0000062709-22-000081","fy":2022,"fp":"Q3","form":"10-Q","filed":"2022-10-20"},{"start":"2021-01-01","end":"2021-12-31","val":348000000,"accn":"0000062709-22-000009","fy":2021,"fp":"FY","form":"10-K","filed":"2022-02-16"},{"start":"2021-01-01","end":"2021-12-31","val":348000000,"accn":"0000062709-23-000014","fy":2022,"fp":"FY","form":"10-K","filed":"2023-02-13"},{"start":"2021-01-01","end":"2021-12-31","val":348000000,"accn":"0000062709-24-000016","fy":2023,"fp":"FY","form":"10-K","filed":"2024-02-12","frame":"CY2021"},{"start":"2022-01-01","end":"2022-03-31","val":105000000,"accn":"0000062709-22-000025","fy":2022,"fp":"Q1","form":"10-Q","filed":"2022-04-21"},{"start":"2022-01-01","end":"2022-03-31","val":105000000,"accn":"0000062709-23-000036","fy":2023,"fp":"Q1","form":"10-Q","filed":"2023-04-20","frame":"CY2022Q1"},{"start":"2022-01-01","end":"2022-06-30","val":194000000,"accn":"0000062709-22-000066","fy":2022,"fp":"Q2","form":"10-Q","filed":"2022-07-21"},{"start":"2022-01-01","end":"2022-06-30","val":194000000,"accn":"0000062709-23-000075","fy":2023,"fp":"Q2","form":"10-Q","filed":"2023-07-20"},{"start":"2022-01-01","end":"2022-09-30","val":283000000,"accn":"0000062709-22-000081","fy":2022,"fp":"Q3","form":"10-Q","filed":"2022-10-20"},{"start":"2022-01-01","end":"2022-09-30","val":283000000,"accn":"0000062709-23-000096","fy":2023,"fp":"Q3","form":"10-Q","filed":"2023-10-19"},{"start":"2022-01-01","end":"2022-12-31","val":367000000,"accn":"0000062709-23-000014","fy":2022,"fp":"FY","form":"10-K","filed":"2023-02-13"},{"start":"2022-01-01","end":"2022-12-31","val":367000000,"accn":"0000062709-24-000016","fy":2023,"fp":"FY","form":"10-K","filed":"2024-02-12"},{"start":"2022-01-01","end":"2022-12-31","val":367000000,"accn":"0000062709-25-000015","fy":2024,"fp":"FY","form":"10-K","filed":"2025-02-10","frame":"CY2022"},{"start":"2023-01-01","end":"2023-03-31","val":99000000,"accn":"0000062709-23-000036","fy":2023,"fp":"Q1","form":"10-Q","filed":"2023-04-20"},{"start":"2023-01-01","end":"2023-03-31","val":99000000,"accn":"0000062709-24-000037","fy":2024,"fp":"Q1","form":"10-Q","filed":"2024-04-18","frame":"CY2023Q1"},{"start":"2023-01-01","end":"2023-06-30","val":191000000,"accn":"0000062709-23-000075","fy":2023,"fp":"Q2","form":"10-Q","filed":"2023-07-20"},{"start":"2023-01-01","end":"2023-06-30","val":191000000,"accn":"0000062709-24-000071","fy":2024,"fp":"Q2","form":"10-Q","filed":"2024-07-18"},{"start":"2023-01-01","end":"2023-09-30","val":273000000,"accn":"0000062709-23-000096","fy":2023,"fp":"Q3","form":"10-Q","filed":"2023-10-19"},{"start":"2023-01-01","end":"2023-09-30","val":273000000,"accn":"0000062709-24-000092","fy":2024,"fp":"Q3","form":"10-Q","filed":"2024-10-17"},{"start":"2023-01-01","end":"2023-12-31","val":363000000,"accn":"0000062709-24-000016","fy":2023,"fp":"FY","form":"10-K","filed":"2024-02-12"},{"start":"2023-01-01","end":"2023-12-31","val":363000000,"accn":"0000062709-25-000015","fy":2024,"fp":"FY","form":"10-K","filed":"2025-02-10"},{"start":"2023-01-01","end":"2023-12-31","val":363000000,"accn":"0000062709-26-000022","fy":2025,"fp":"FY","form":"10-K","filed":"2026-02-09","frame":"CY2023"},{"start":"2024-01-01","end":"2024-03-31","val":103000000,"accn":"0000062709-24-000037","fy":2024,"fp":"Q1","form":"10-Q","filed":"2024-04-18"},{"start":"2024-01-01","end":"2024-03-31","val":103000000,"accn":"0000062709-25-000028","fy":2025,"fp":"Q1","form":"10-Q","filed":"2025-04-17","frame":"CY2024Q1"},{"start":"2024-01-01","end":"2024-06-30","val":193000000,"accn":"0000062709-24-000071","fy":2024,"fp":"Q2","form":"10-Q","filed":"2024-07-18"},{"start":"2024-01-01","end":"2024-06-30","val":193000000,"accn":"0000062709-25-000069","fy":2025,"fp":"Q2","form":"10-Q","filed":"2025-07-17"},{"start":"2024-01-01","end":"2024-09-30","val":283000000,"accn":"0000062709-24-000092","fy":2024,"fp":"Q3","form":"10-Q","filed":"2024-10-17"},{"start":"2024-01-01","end":"2024-09-30","val":283000000,"accn":"0000062709-25-000125","fy":2025,"fp":"Q3","form":"10-Q","filed":"2025-10-16"},{"start":"2024-01-01","end":"2024-12-31","val":368000000,"accn":"0000062709-25-000015","fy":2024,"fp":"FY","form":"10-K","filed":"2025-02-10"},{"start":"2024-01-01","end":"2024-12-31","val":368000000,"accn":"0000062709-26-000022","fy":2025,"fp":"FY","form":"10-K","filed":"2026-02-09","frame":"CY2024"},{"start":"2025-01-01","end":"2025-03-31","val":112000000,"accn":"0000062709-25-000028","fy":2025,"fp":"Q1","form":"10-Q","filed":"2025-04-17"},{"start":"2025-01-01","end":"2025-03-31","val":112000000,"accn":"0000062709-26-000098","fy":2026,"fp":"Q1","form":"10-Q","filed":"2026-04-16","frame":"CY2025Q1"},{"start":"2025-01-01","end":"2025-06-30","val":210000000,"accn":"0000062709-25-000069","fy":2025,"fp":"Q2","form":"10-Q","filed":"2025-07-17"},{"start":"2025-01-01","end":"2025-06-30","val":210000000,"accn":"0000062709-26-000195","fy":2026,"fp":"Q2","form":"10-Q","filed":"2026-07-21"},{"start":"2025-01-01","end":"2025-09-30","val":305000000,"accn":"0000062709-25-000125","fy":2025,"fp":"Q3","form":"10-Q","filed":"2025-10-16"},{"start":"2025-01-01","end":"2025-09-30","val":305000000,"accn":"0000062709-26-000258","fy":2026,"fp":"Q3","form":"10-Q","filed":"2026-10-15"},{"start":"2025-01-01","end":"2025-12-31","val":394000000,"accn":"0000062709-26-000022","fy":2025,"fp":"FY","form":"10-K","filed":"2026-02-09","frame":"CY2025"},{"start":"2026-01-01","end":"2026-03-31","val":139000000,"accn":"0000062709-26-000098","fy":2026,"fp":"Q1","form":"10-Q","filed":"2026-04-16","frame":"CY2026Q1"},{"start":"2026-01-01","end":"2026-06-30","val":235000000,"accn":"0000062709-26-000195","fy":2026,"fp":"Q2","form":"10-Q","filed":"2026-07-21"},{"start":"2026-01-01","end":"2026-09-30","val":329000000,"accn":"0000062709-26-000258","fy":2026,"fp":"Q3","form":"10-Q","filed":"2026-10-15"}]}}