Restructuring (Narrative) (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) position	Jun. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring	$ 14,534	$ 4,511	$ 48,485	$ 14,161
Restructuring Reserve	12,635		12,635		$ 2,780
Employee Severance and Related Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring			43,915
Consolidation of Leased Facilities [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring			$ 3,516
2015 Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Number of full-time positions eliminated | position			700
Restructuring	13,400		$ 46,400
Restructuring Reserve	11,091		11,091		0
2015 Restructuring Program [Member] | Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Total expected restructuring cost	52,000		52,000
2015 Restructuring Program [Member] | Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Total expected restructuring cost	57,000		57,000
2015 Restructuring Program [Member] | Employee Severance and Related Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring			41,855
2015 Restructuring Program [Member] | Employee Severance and Related Costs [Member] | Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Total expected restructuring cost	47,000		47,000
2015 Restructuring Program [Member] | Employee Severance and Related Costs [Member] | Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Total expected restructuring cost	50,000		50,000
2015 Restructuring Program [Member] | Consolidation of Leased Facilities [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring			3,516
2015 Restructuring Program [Member] | Consolidation of Leased Facilities [Member] | Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Total expected restructuring cost	5,000		5,000
2015 Restructuring Program [Member] | Consolidation of Leased Facilities [Member] | Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Total expected restructuring cost	7,000		$ 7,000
2014 Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Number of full-time positions eliminated | position			325
Restructuring costs incurred since inception	22,500		$ 22,500
Restructuring Reserve	1,544		1,544		$ 2,780
2014 Restructuring Program [Member] | Employee Severance and Related Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring			2,060
2014 Restructuring Program [Member] | Consolidation of Leased Facilities [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring			0
Enterprise and Service Provider Division [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	12,600		12,600
Enterprise and Service Provider Division [Member] | 2015 Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring	13,111	0	45,866	0
Enterprise and Service Provider Division [Member] | 2014 Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring	$ 1,176	$ 2,091	$ 2,010	$ 7,971