Stock Transactions And Stock-Based Compensation (Summary Of Options Outstanding) (Details) shares in Millions	12 Months Ended
	Dec. 31, 2019 $ / shares shares
$19.89 to $41.64
Options, exercise price, lower range limit	$ 19.89
Options, exercise price, upper range limit	$ 41.64
Outstanding, shares (in millions) | shares	1.2
Outstanding, average exercise price	$ 36.79
Outstanding, average remaining life (in years)	2 years
Exercisable, shares (in millions) | shares	1.2
Exercisable, average exercise price	$ 36.79
$41.65 to $62.18
Options, exercise price, lower range limit	41.65
Options, exercise price, upper range limit	$ 62.18
Outstanding, shares (in millions) | shares	2.2
Outstanding, average exercise price	$ 54.47
Outstanding, average remaining life (in years)	4 years
Exercisable, shares (in millions) | shares	2.2
Exercisable, average exercise price	$ 54.51
$62.19 to $83.27
Options, exercise price, lower range limit	62.19
Options, exercise price, upper range limit	$ 83.27
Outstanding, shares (in millions) | shares	4.0
Outstanding, average exercise price	$ 67.03
Outstanding, average remaining life (in years)	6 years
Exercisable, shares (in millions) | shares	2.2
Exercisable, average exercise price	$ 67.12
$83.28 to $101.64
Options, exercise price, lower range limit	83.28
Options, exercise price, upper range limit	$ 101.64
Outstanding, shares (in millions) | shares	5.8
Outstanding, average exercise price	$ 92.70
Outstanding, average remaining life (in years)	8 years
Exercisable, shares (in millions) | shares	1.3
Exercisable, average exercise price	$ 90.74
$101.65 to $142.99
Options, exercise price, lower range limit	101.65
Options, exercise price, upper range limit	$ 142.99
Outstanding, shares (in millions) | shares	3.8
Outstanding, average exercise price	$ 116.76
Outstanding, average remaining life (in years)	9 years
Exercisable, shares (in millions) | shares	0.1
Exercisable, average exercise price	$ 113.57