Segment Information (Total Revenues of Reportable Segments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 2,833,020	$ 2,590,642	$ 5,490,193	$ 5,191,744
US Traditional Segment Reporting Information [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	1,333,027	1,275,331	2,611,719	2,472,255
US Non-Traditional Segment Reporting Information [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	293,448	301,991	582,069	616,091
Canada Segment Reporting Information [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	309,113	295,325	586,862	592,414
EMEA [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	391,318	310,169	757,175	617,756
Asia Pacific [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	483,171	383,978	898,200	793,829
Corporate and Other [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 22,943	$ 23,848	$ 54,168	$ 99,399