Stock-Based Compensation (Schedule Of Option Activity And Changes) (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) $ / shares shares
Options
Options, Outstanding, beginning balance | shares	1,269,601
Options, Granted | shares	173,195
Options, Exercised | shares	(323,182)
Options, Cancelled | shares	(3,660)
Options, Outstanding, ending balance | shares	1,115,954
Options, Exercisable, ending balance | shares	628,926
Weighted Average Exercise Price
Weighted Average Exercise Price, Outstanding, beginning balance (in dollars per share) | $ / shares	$ 41.04
Weighted Average Exercise Price, Granted (in dollars per share) | $ / shares	107.75
Weighted Average Exercise Price, Exercised (in dollars per share) | $ / shares	28.81
Weighted Average Exercise Price, Cancelled (in dollars per share) | $ / shares	77.16
Weighted Average Exercise Price, Outstanding, ending balance (in dollars per share) | $ / shares	54.82
Weighted Average Exercise Price, Exercisable, ending balance (in dollars per share) | $ / shares	$ 39.05
Weighted Average Remaining Term (Years) [Abstract]
Weighted Average Remaining Term (Years), Outstanding	6 years 1 month 6 days
Weighted Average Remaining Term (Years), Exercisable	4 years 6 months
Aggregate Intrinsic Value [Abstract]
Aggregate Intrinsic Value, Outstanding | $	$ 20
Aggregate Intrinsic Value, Exercisable | $	$ 17