Nature of Operations (Details) colleague in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($) colleague country	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) colleague country	Jun. 30, 2019 USD ($)
Nature of Operations [Line Items]
Entity number of colleagues | colleague	76		76
Revenue	$ 4,189	$ 4,349	$ 8,840	$ 8,420
Number of countries in which entity operates (more than) | country	130		130
Marsh & McLennan Companies, Inc.
Nature of Operations [Line Items]
Revenue			$ 17,000