Other Financial Information, Other Long Term Assets (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2015	Dec. 31, 2014	Oct. 01, 2014
Other Financial Information [Line Items]
Privately-held investments	$ 92.1	$ 89.9
Licensed software	8.0	8.6
Federal income tax receivable	28.9	20.0
Customer financing receivable	3.0	16.9
Inventory	11.3	8.0
Prepaid costs, deposits, and other	61.6	35.5
Promissory note in connection with the sale of Junos Pulse	125.0	125.0
Interest Receivable	4.7	0.0
Other long-term assets	334.6	$ 303.9
Scheduled interest payments not received	3.1
Interest income	$ 1.6
Junos Pulse [Member]
Other Financial Information [Line Items]
Promissory note in connection with the sale of Junos Pulse			$ 125.0
Consideration			230.7
Cash Consideration			105.7
Working capital adjustment			$ 19.3