Earnings (Loss) Per Share (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019		Dec. 31, 2018
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income (loss)	$ 119.6	$ (327.3)	$ (140.8)
Basic (in shares)	355,544,632	307,076,397	118,261,955
Dilutive effect of equity-based compensation and warrants (in shares)	4,595,691	0	0
Weighted-average number of ordinary shares outstanding - diluted (in shares)	360,140,323	307,076,397	118,261,955
Net income per share
Basic (USD per share)	$ 0.34	$ (1.07)	$ (1.19)
Diluted (USD per share)	$ 0.33	$ (1.07)	$ (1.19)
Common stock shares outstanding (in shares)	375,801,857	342,024,612
Share Capital
Net income per share
Common stock shares outstanding (in shares)	375,801,857	342,024,612	118,261,955	[1]	118,261,955	[1]
Previously Reported | Share Capital
Net income per share
Common stock shares outstanding (in shares)			1,000,000.0		1,000,000

[1] The shares and earnings per share available to holders of the Company’s common shares, prior to the Business Combination, have been recasted as shares reflecting the exchange ratio established in the Business Combination (1.0 Vertiv Holdings share to 118.261955 Vertiv Holdings Co shares).