Goodwill and Other Intangible Assets (Prior Year Acquisitions) (Other 2014 Acquisitions) (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($)
April 2014 Acquisition [Member]
Business Combinations [Line Items]
Business combinations, effective date	Apr. 01, 2014
Business combinations, percentage of voting interests acquired	100.00%
Business combinations, description of acquired entity	a telecommunications services firm, specializing in the installation of in-home security systems
January 2014 Acquisition [Member]
Business Combinations [Line Items]
Business combinations, effective date	Jan. 01, 2014
Business combinations, percentage of voting interests acquired	100.00%
Business combinations, description of acquired entity	a telecommunications services firm, specializing in the engineering, installation, furnishing and integration of telecommunications equipment
Other 2014 Acquisitions [Member]
Business Combinations [Line Items]
Business combinations, aggregate purchase price, as adjusted (in dollars)	$ 40.1