Restructuring Charges (Number of Positions Eliminated Rollfoward) (Details) - employee	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Restructuring and Related Cost, Number of Positions Eliminated [Roll Forward]
Planned reductions - January 1	69	47
Additional planned reductions	158	102
Actual reductions and reversals	(134)	(45)
Planned reductions - March 31	93	104