Earnings Per Share (Narrative) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended		67 Months Ended
	Aug. 08, 2016	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Aug. 08, 2016
Earnings Per Share
Common stock repurchased, shares		2,075	1,987	3,306	2,637
Common stock repurchased, average price per share		$ 262.17	$ 221.50	$ 259.14	$ 218.05
Common stock repurchased, value		$ 544,165	$ 440,129	$ 856,802	$ 574,932
Subsequent event [Member]
Earnings Per Share
Common stock repurchased, shares	100					54,600
Common stock repurchased, average price per share	$ 277.44					$ 113.98
Common stock repurchased, value	$ 8,300					$ 6,200,000