Special charges (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014
Technology Products [Member]
Special Charges [Abstract]
Balance beginning of period		$ 12.1
Charged to expense		8.4
Paid or otherwise settled		(12.1)
Balance end of period	8.4	8.4
Special charges	1.6	10.0
Technology Products [Member] | Workforce and Personnel Costs [Member]
Special Charges [Abstract]
Balance beginning of period		7.0
Charged to expense		8.3
Paid or otherwise settled		(10.7)
Balance end of period	4.6	4.6
Technology Products [Member] | Other Exit Costs [Member]
Special Charges [Abstract]
Balance beginning of period		5.1
Charged to expense	(0.4)	0.1
Paid or otherwise settled		(1.4)
Balance end of period	3.8	3.8
Technology Products [Member] | Closing of Underperforming Retail Stores [Member]
Special Charges [Abstract]
Special charges		0.2
Technology Products [Member] | Facility Closing and Exit from PC Manufacturing Business [Member]
Special Charges [Abstract]
Special charges		0.2
Technology Products [Member] | Legal And Professional Fees [Member]
Special Charges [Abstract]
Special charges	0.1	0.7
Technology Products [Member] | Workforce Reductions and Other Exit Costs [Member]
Special Charges [Abstract]
Special charges	1.8	8.3
Technology Products [Member] | European Shared Services Center [Member]
Special Charges [Abstract]
Recruitment costs	0.1	0.5
Corporate and Other [Member] | Severance [Member]
Special Charges [Abstract]
Special charges	$ 0.1	$ 0.1