Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Net sales	$ 1,037.9	$ 1,108.6	$ 949.2	$ 1,090.3	$ 1,103.3	$ 1,204.0	$ 1,196.4	$ 1,087.3	$ 4,186.0	$ 4,591.0	$ 4,481.7
United States
Disaggregation of Revenue [Line Items]
Net sales									3,860.4	4,190.5	4,040.6
International
Disaggregation of Revenue [Line Items]
Net sales									325.6	400.5	441.1
Electrical Solutions
Disaggregation of Revenue [Line Items]
Net sales									2,263.6	2,625.7	2,660.6
Electrical Solutions | Commercial and Industrial
Disaggregation of Revenue [Line Items]
Net sales									762.1	902.1	910.8
Electrical Solutions | Construction and Energy
Disaggregation of Revenue [Line Items]
Net sales									715.4	808.7	799.7
Electrical Solutions | Lighting
Disaggregation of Revenue [Line Items]
Net sales									786.1	914.9	950.1
Electrical Solutions | United States
Disaggregation of Revenue [Line Items]
Net sales									2,049.5	2,358.2	2,365.4
Electrical Solutions | International
Disaggregation of Revenue [Line Items]
Net sales									214.1	267.5	295.2
Utility Solutions
Disaggregation of Revenue [Line Items]
Net sales									1,922.4	1,965.3	1,821.1
Utility Solutions | Power Systems
Disaggregation of Revenue [Line Items]
Net sales									1,343.0	1,283.1	1,210.0
Utility Solutions | Aclara
Disaggregation of Revenue [Line Items]
Net sales									579.4	682.2	611.1
Utility Solutions | United States
Disaggregation of Revenue [Line Items]
Net sales									1,810.9	1,832.3	1,675.2
Utility Solutions | International
Disaggregation of Revenue [Line Items]
Net sales									$ 111.5	$ 133.0	$ 145.9