Nature of Operations	6 Months Ended
Jun. 30, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Nature of Operations	Note 1 — Nature of Operations Willis Towers Watson plc is a leading global advisory, broking and solutions company that helps clients around the world turn risk into a path for growth. The Company has more than 43,000 employees servicing clients in more than 140 countries. We offer our clients a broad range of services and solutions to help identify and control risks, and to enhance business performance by improving the attraction, retention and engagement of talent. Our risk identification and control services include strategic risk consulting (including providing actuarial analysis), a variety of due diligence services, the provision of practical on-site risk control services (such as health and safety and property loss control consulting), and analytical and advisory services (such as hazard modeling and reinsurance optimization studies). We also assist our clients with planning for managing incidents or crises when they occur. These services include contingency planning, security audits and product tampering plans. We help our clients enhance business performance by delivering consulting services, technology and solutions to help anticipate, identify and capitalize on emerging opportunities in human capital management. Our services and solutions encompass such areas as employee benefits, total rewards, talent and benefits outsourcing. In addition, we provide investment advice to help our clients develop disciplined and efficient strategies to meet their investment goals. As an insurance broker, we act as an intermediary between our clients and insurance carriers by advising on their risk management requirements, helping them to determine the best means of managing risk and negotiating and placing insurance with insurance carriers through our global distribution network. We operate a private Medicare marketplace in the U.S. through which, along with our active employee marketplace, we help our clients move to a more sustainable economic model by capping and controlling the costs associated with healthcare benefits. We are not an insurance company, and therefore we do not underwrite insurable risks for our own account. We believe our broad perspective allows us to see the critical intersections between talent, assets and ideas - the dynamic formula that drives business performance.

Nature of Operations

6 Months Ended

Jun. 30, 2019

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Note 1 — Nature of Operations

Willis Towers Watson plc is a leading global advisory, broking and solutions company that helps clients around the world turn risk into a path for growth. The Company has more than 43,000 employees servicing clients in more than 140 countries.

We offer our clients a broad range of services and solutions to help identify and control risks, and to enhance business performance by improving the attraction, retention and engagement of talent.

Our risk identification and control services include strategic risk consulting (including providing actuarial analysis), a variety of due diligence services, the provision of practical on-site risk control services (such as health and safety and property loss control consulting), and analytical and advisory services (such as hazard modeling and reinsurance optimization studies). We also assist our clients with planning for managing incidents or crises when they occur. These services include contingency planning, security audits and product tampering plans.

We help our clients enhance business performance by delivering consulting services, technology and solutions to help anticipate, identify and capitalize on emerging opportunities in human capital management. Our services and solutions encompass such areas as employee benefits, total rewards, talent and benefits outsourcing. In addition, we provide investment advice to help our clients develop disciplined and efficient strategies to meet their investment goals.

As an insurance broker, we act as an intermediary between our clients and insurance carriers by advising on their risk management requirements, helping them to determine the best means of managing risk and negotiating and placing insurance with insurance carriers through our global distribution network.

We operate a private Medicare marketplace in the U.S. through which, along with our active employee marketplace, we help our clients move to a more sustainable economic model by capping and controlling the costs associated with healthcare benefits.

We are not an insurance company, and therefore we do not underwrite insurable risks for our own account. We believe our broad perspective allows us to see the critical intersections between talent, assets and ideas - the dynamic formula that drives business performance.