Stock-Based Compensation (Summary Of Option Activity Under The MSIP) (Details) - Stock Options [Member] - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Weighted Average Exercise Price
Granted to employees (in dollars per share)	$ 40.04	$ 55.18	$ 39.27
MSIP and Omnibus Incentive Plan [Member]
Stock Options
Total outstanding at the beginning of the period (in shares)	1,342,843
Granted to employees (in shares)	634,743
Exercised (in shares)	(407,337)
Forfeited (in shares)	(339,728)
Expired (in shares)	(1)
Total outstanding at the end of the period (in shares)	1,230,520	1,342,843
Total exercisable at the end of the period (in shares)	261,788
Weighted Average Exercise Price
Total outstanding at the beginning of the period (in dollars per share)	$ 29.34
Granted to employees (in dollars per share)	40.04
Exercised (in dollars per share)	23.82
Forfeited (in dollars per share)	34.38
Expired (in dollars per share)	26.81
Total outstanding at the end of the period (in dollars per share)	35.30	$ 29.34
Total exercisable at the end of the period (in dollars per share)	$ 29.38
Total Outstanding, Beginning of Period	$ 10
Total Outstanding, End of Period	5	$ 10
Total exercisable, End of Period	$ 2
Weighted Average Remaining Contractual Term
Total outstanding at the end of the period	7 years 4 months 9 days	8 years 3 days
Total exercisable at the end of the period	7 years 2 months 1 day