Stockholders' Equity (Activity for Stock Option Awards) (Details) shares in Thousands	3 Months Ended
	Dec. 31, 2017 $ / shares shares
Stock-Based Compensation
Number of options, beginning balance | shares	5,236
Weighted Average Exercise Price Per Share, beginning balance | $ / shares	$ 39.58
Options granted, Number of options | shares	744
Options granted, Weighted Average Exercise Price Per Share | $ / shares	$ 78.97
Options exercised, Number of options | shares	(34)
Options exercised, Weighted Average Exercise Price Per Share | $ / shares	$ 41.13
Options forfeited, Number of options | shares	(9)
Options forfeited, Weighted Average Exercise Price Per Share | $ / shares	$ 55.61
Number of options, ending balance | shares	5,937
Weighted Average Exercise Price Per Share, ending balance | $ / shares	$ 44.48