Stock Transactions and Stock-Based Compensation (Summary of Options Outstanding) (Details) shares in Millions	12 Months Ended
	Dec. 31, 2015 $ / shares shares
$26.29 to $37.74
Options, exercise price, lower range limit	$ 26.29
Options, exercise price, upper range limit	$ 37.74
Outstanding, shares (in millions) | shares	4.1
Outstanding, average exercise price	$ 32.92
Outstanding, average remaining life (in years)	3 years
Exercisable, shares (in millions) | shares	4.1
Exercisable, average exercise price	$ 32.92
$37.75 to $51.08
Options, exercise price, lower range limit	37.75
Options, exercise price, upper range limit	$ 51.08
Outstanding, shares (in millions) | shares	4.3
Outstanding, average exercise price	$ 43.92
Outstanding, average remaining life (in years)	4 years
Exercisable, shares (in millions) | shares	3.6
Exercisable, average exercise price	$ 42.78
$51.09 to $67.16
Options, exercise price, lower range limit	51.09
Options, exercise price, upper range limit	$ 67.16
Outstanding, shares (in millions) | shares	3.9
Outstanding, average exercise price	$ 55.25
Outstanding, average remaining life (in years)	7 years
Exercisable, shares (in millions) | shares	1.2
Exercisable, average exercise price	$ 53.42
$67.17 to $82.22
Options, exercise price, lower range limit	67.17
Options, exercise price, upper range limit	$ 82.22
Outstanding, shares (in millions) | shares	4.4
Outstanding, average exercise price	$ 73.74
Outstanding, average remaining life (in years)	8 years
Exercisable, shares (in millions) | shares	0.8
Exercisable, average exercise price	$ 71.65
$82.23 to $93.54
Options, exercise price, lower range limit	82.23
Options, exercise price, upper range limit	$ 93.54
Outstanding, shares (in millions) | shares	3.4
Outstanding, average exercise price	$ 87.87
Outstanding, average remaining life (in years)	9 years
Exercisable, shares (in millions) | shares	0.1
Exercisable, average exercise price	$ 84.52