Stockholders' Equity (Share Repurchase) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		12 Months Ended
	Jan. 31, 2018	Sep. 28, 2018	Sep. 29, 2017	Sep. 30, 2016
Share Repurchase [Line Items]
Share repurchase authorized date	Jan. 31, 2018
Share repurchase program		$ 759.5	$ 432.3	$ 525.6
Share repurchase program (in shares)		7.7	4.7
Treasury stock, average price per share (in dollars per share)		$ 98.84	$ 92.97
Remaining shares available under share repurchase program		$ 413.0
Authorized repurchased amount		$ 1,000.0
Stock Repurchase Program Expiration Date	Jan. 31, 2020