Parent Company Information - Condensed Balance Sheets (Details) - USD ($) $ / shares in Units, $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Jul. 12, 2018	Dec. 31, 2017	Dec. 31, 2016
Assets
Cash	$ 813.2	$ 895.3		$ 405.6	$ 382.3
Total assets	7,163.4	6,546.0
Liabilities
Total liabilities	5,862.1	5,185.9
Equity
Ordinary shares, nominal value $0.10 per share, 219.5 shares issued and outstanding at December 31, 2019 and ordinary shares nominal value $0.10 per share, 216.6 shares issued and outstanding at December 31, 2018	22.0	21.7
Additional paid-in capital	2,819.5	2,791.2
Treasury stock, at cost	(0.4)	0.0
Accumulated deficit	(1,297.0)	(1,298.4)
Accumulated other comprehensive loss	(242.8)	(154.4)
Total equity	1,301.3	1,360.1
Total liabilities and shareholders' equity	$ 7,163.4	$ 6,546.0
Ordinary shares, nominal value per share (in dollars per share)	$ 0.10	$ 0.1	$ 0.01
Ordinary shares issued (in shares)	219,500,000.0	216,600,000.0
Ordinary shares outstanding (in shares)	219,500,000.0	216,600,000.0
Cushman & Wakefield plc
Assets
Cash	$ 10.7	$ 10.5
Accounts receivables	85.4	34.9
Investments in subsidiaries	1,270.9	1,348.9
Total assets	1,367.0	1,394.3
Liabilities
Trade and other payables	65.7	34.2
Total liabilities	65.7	34.2
Equity
Ordinary shares, nominal value $0.10 per share, 219.5 shares issued and outstanding at December 31, 2019 and ordinary shares nominal value $0.10 per share, 216.6 shares issued and outstanding at December 31, 2018	22.0	21.7
Additional paid-in capital	2,819.5	2,791.2
Treasury stock, at cost	(0.4)	0.0
Accumulated deficit	(1,297.0)	(1,298.4)
Accumulated other comprehensive loss	(242.8)	(154.4)
Total equity	1,301.3	1,360.1
Total liabilities and shareholders' equity	$ 1,367.0	$ 1,394.3