Business Acquisitions - Narrative (Details)		1 Months Ended	3 Months Ended			12 Months Ended
	Feb. 02, 2018 USD ($)	Feb. 15, 2018 USD ($)	Dec. 31, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($) acquisition	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Jan. 31, 2018 USD ($)
Business Acquisition [Line Items]
Goodwill			$ 1,089,000,000			$ 1,089,000,000	$ 991,000,000	$ 928,500,000
Payments to acquire businesses, net of cash acquired						184,100,000	$ 173,400,000	$ 163,400,000
Power
Business Acquisition [Line Items]
Number of businesses acquired | acquisition					2
Consideration transferred to acquire business					$ 10,100,000
Intangible assets acquired					3,400,000
Goodwill					5,000,000
Goodwill, expected to be tax deductible					$ 2,700,000
Intangible assets, useful life					13 years
iDevices, LLC
Business Acquisition [Line Items]
Consideration transferred to acquire business				$ 59,200,000
Intangible assets acquired				9,600,000
Goodwill				$ 45,900,000
Intangible assets, useful life				12 years
Advance Engineering Corporation and Perfect Pipe & Supply Corporation
Business Acquisition [Line Items]
Consideration transferred to acquire business				$ 32,500,000
Intangible assets acquired				16,800,000
Goodwill				$ 12,800,000
Intangible assets, useful life				18 years
Meramec Instrument Transformer Company
Business Acquisition [Line Items]
Consideration transferred to acquire business			69,700,000
Intangible assets acquired			33,800,000			33,800,000
Goodwill			$ 24,800,000			$ 24,800,000
Intangible assets, useful life			21 years
Subsequent Event | Aclara
Business Acquisition [Line Items]
Consideration transferred to acquire business	$ 1,100,000,000	$ 1,100,000,000
Term Loan Agreement | Line of Credit | Subsequent Event
Business Acquisition [Line Items]
Line of credit, maximum borrowing capacity	500,000,000								$ 500,000,000
Notes 2028 Term | Senior Notes | Subsequent Event
Business Acquisition [Line Items]
Face amount	$ 450,000,000