Stock Plans (Activity for Performance Share Units) (Details)	12 Months Ended
	Dec. 31, 2016 $ / shares shares
Performance Shares [Member]
Number of Shares (in shares):
Beginning Balance (in shares) | shares	0
Granted (in shares) | shares	428,400
Vested (in shares) | shares	0
Forfeited (in shares) | shares	(830)
Ending Balance (in shares) | shares	427,570
Performance Share Units, TSR Relative To Customer Peer Group [Member]
Weighted-Average Grant Date Fair Value:
Beginning Balance (in dollars per share)	$ 0.00
Granted (in dollars per share)	104.60
Vested (in dollars per share)	0.00
Forfeited (in dollars per share)	104.60
Ending Balance (in dollars per share)	104.60
Performance Share Units, Other Performance Factors [Member]
Weighted-Average Grant Date Fair Value:
Beginning Balance (in dollars per share)	0.00
Granted (in dollars per share)	89.02
Vested (in dollars per share)	0.00
Forfeited (in dollars per share)	89.02
Ending Balance (in dollars per share)	$ 89.02