Share Repurchase Program (Narrative) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands			1 Months Ended	3 Months Ended		9 Months Ended		70 Months Ended
	May 27, 2016	Feb. 10, 2016	Nov. 08, 2016	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Nov. 08, 2016
Share Repurchase Program
Increase in authorized amount	$ 750,000	$ 750,000
Cumulative authorized amount	$ 7,000,000
Authorization effective period	3 years	3 years
Remaining balance under share repurchase program				$ 683,500		$ 683,500
Common stock repurchased, shares				367	1,147	3,673	3,784
Common stock repurchased, average price per share				$ 281.04	$ 238.97	$ 261.32	$ 224.39
Common stock repurchased, value				$ 102,941	$ 274,213	$ 959,743	$ 849,145
Subsequent event [Member]
Share Repurchase Program
Common stock repurchased, shares			600					55,600
Common stock repurchased, average price per share			$ 269.29					$ 116.76
Common stock repurchased, value			$ 169,900					$ 6,500,000