Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Net sales	$ 1,162.0	$ 1,070.7	$ 3,064.9	$ 3,259.7
Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Net sales	865.2	797.6	2,247.7	2,472.3
Transferred over Time
Disaggregation of Revenue [Line Items]
Net sales	296.8	273.1	817.2	787.4
Critical infrastructure & solutions
Disaggregation of Revenue [Line Items]
Net sales	662.3	574.9	1,678.1	1,820.4
Critical infrastructure & solutions | Restatement Adjustment
Disaggregation of Revenue [Line Items]
Net sales		(52.6)		(118.4)
Services & spares
Disaggregation of Revenue [Line Items]
Net sales	341.9	342.5	964.9	985.4
Services & spares | Restatement Adjustment
Disaggregation of Revenue [Line Items]
Net sales		17.3		28.1
Integrated rack solutions
Disaggregation of Revenue [Line Items]
Net sales	157.8	153.3	421.9	453.9
Integrated rack solutions | Restatement Adjustment
Disaggregation of Revenue [Line Items]
Net sales		35.3		90.3
Americas
Disaggregation of Revenue [Line Items]
Net sales	532.0	545.7	1,483.3	1,675.4
Americas | Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Net sales	376.7	383.7	1,022.3	1,217.1
Americas | Transferred over Time
Disaggregation of Revenue [Line Items]
Net sales	155.3	162.0	461.0	458.3
Americas | Critical infrastructure & solutions
Disaggregation of Revenue [Line Items]
Net sales	278.7	286.3	769.9	937.1
Americas | Services & spares
Disaggregation of Revenue [Line Items]
Net sales	168.3	180.6	491.0	505.5
Americas | Integrated rack solutions
Disaggregation of Revenue [Line Items]
Net sales	85.0	78.8	222.4	232.8
Asia Pacific
Disaggregation of Revenue [Line Items]
Net sales	379.6	323.7	926.3	906.1
Asia Pacific | Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Net sales	302.6	255.0	720.3	706.5
Asia Pacific | Transferred over Time
Disaggregation of Revenue [Line Items]
Net sales	77.0	68.7	206.0	199.6
Asia Pacific | Critical infrastructure & solutions
Disaggregation of Revenue [Line Items]
Net sales	245.3	191.7	565.2	527.9
Asia Pacific | Services & spares
Disaggregation of Revenue [Line Items]
Net sales	95.2	93.7	263.5	268.2
Asia Pacific | Integrated rack solutions
Disaggregation of Revenue [Line Items]
Net sales	39.1	38.3	97.6	110.0
Europe, Middle East, & Africa
Disaggregation of Revenue [Line Items]
Net sales	250.4	201.3	655.3	678.2
Europe, Middle East, & Africa | Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Net sales	185.9	158.9	505.1	548.7
Europe, Middle East, & Africa | Transferred over Time
Disaggregation of Revenue [Line Items]
Net sales	64.5	42.4	150.2	129.5
Europe, Middle East, & Africa | Critical infrastructure & solutions
Disaggregation of Revenue [Line Items]
Net sales	138.3	96.9	343.0	355.4
Europe, Middle East, & Africa | Services & spares
Disaggregation of Revenue [Line Items]
Net sales	78.4	68.2	210.4	211.7
Europe, Middle East, & Africa | Integrated rack solutions
Disaggregation of Revenue [Line Items]
Net sales	$ 33.7	$ 36.2	$ 101.9	$ 111.1