Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended																12 Months Ended
	Sep. 27, 2019		Jun. 28, 2019		Mar. 29, 2019		Dec. 28, 2018		Sep. 28, 2018		Jun. 29, 2018		Mar. 30, 2018		Dec. 29, 2017		Sep. 27, 2019		Sep. 28, 2018		Sep. 29, 2017
Selected Quarterly Financial Information [Abstract]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 827.4		$ 767.0		$ 810.4		$ 972.0		$ 1,008.4		$ 894.3		$ 913.4		$ 1,051.9		$ 3,376.8		$ 3,868.0		$ 3,651.4
Gross Profit	406.0		312.5		400.2		485.1		503.6		451.6		458.7		536.8		1,603.8		1,950.7		1,841.8
Net income	$ 210.6		$ 144.1		$ 214.0		$ 284.9		$ 285.5		$ 286.5		$ 276.0		$ 70.4		$ 853.6		$ 918.4		$ 1,010.2
Net income, basic (in dollars per share)	$ 1.23	[1]	$ 0.83	[1]	$ 1.23	[1]	$ 1.61	[1]	$ 1.60	[1]	$ 1.58	[1]	$ 1.51	[1]	$ 0.38	[1]	$ 4.92	[1]	$ 5.06	[1]	$ 5.48
Net income, diluted (in dollars per share)	$ 1.22	[1]	$ 0.83	[1]	$ 1.23	[1]	$ 1.60	[1]	$ 1.58	[1]	$ 1.57	[1]	$ 1.50	[1]	$ 0.38	[1]	$ 4.89	[1]	$ 5.01	[1]	$ 5.41

[1] Earnings per share calculations for each of the quarters are based on the weighted average number of shares outstanding and included common stock equivalents in each period. Therefore, the sums of the quarters do not necessarily equal the full year earnings per share.