Unaudited Condensed Consolidated Statements of Shareholders' Equity (Deficit) - USD ($) $ in Millions		Total		Share Capital	Additional Paid in Capital		Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2020				342,024,612
Beginning balance at Dec. 31, 2020		$ 512.1		$ 0.0	$ 1,791.8		$ (1,331.2)	$ 51.5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		31.7					31.7
Exercise of employee stock options (in shares)				76,047
Exercise of employee stock options		0.9			0.9
Employee 401K match with Vertiv stock (in shares)				69,309
Employee 401K match with Vertiv stock		1.3	[1]		1.3
Exercise of warrants (in shares)	[1]			9,346,822
Exercise of warrants		176.0			176.0	[1]
Stock-based compensation		5.6			5.6
Other comprehensive income (loss), net of tax		1.1						1.1
Ending balance (in shares) at Mar. 31, 2021				351,516,790
Ending balance at Mar. 31, 2021		$ 728.7		$ 0.0	1,975.6		(1,299.5)	52.6
Beginning balance (in shares) at Dec. 31, 2021		375,801,857		375,801,857
Beginning balance at Dec. 31, 2021		$ 1,417.7		$ 0.0	2,597.5		(1,215.4)	35.6
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		8.5					8.5
Exercise of employee stock options (in shares)				89,566
Exercise of employee stock options		1.0			1.0
Employee 401K match with Vertiv stock (in shares)				100,541
Employee 401K match with Vertiv stock		2.3			2.3
Stock-based compensation		6.6			6.6
Other comprehensive income (loss), net of tax		$ 18.0						18.0
Ending balance (in shares) at Mar. 31, 2022		375,991,964		375,991,964
Ending balance at Mar. 31, 2022		$ 1,454.1		$ 0.0	$ 2,607.4		$ (1,206.9)	$ 53.6

[1] The exercise of warrants includes $107.5 of cash received during the three months ended March 31, 2021 for the exercise of Public Warrants.