Fair Value (Tables)

6 Months Ended

Mar. 27, 2020

Fair Value Disclosures [Abstract]

Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis

Assets and liabilities recorded at fair value on a recurring basis consisted of the following (in millions):         

	As of March 27, 2020								As of September 27, 2019
			Fair Value Measurements								Fair Value Measurements
	Total		Level 1		Level 2		Level 3		Total		Level 1		Level 2		Level 3
Assets
Cash and cash equivalents*	$	912.4	$	772.7	$	139.7	$	—	$	851.3	$	809.5	$	41.8	$	—
U.S. Treasury and government securities	84.2		40.3		43.9		—		54.2		28.4		25.8		—
Corporate bonds and notes	89.8		—		89.8		—		72.1		—		72.1		—
Municipal bonds	21.6		—		21.6		—		104.6		—		104.6		—
Total	$	1,108.0	$	813.0	$	295.0	$	—	$	1,082.2	$	837.9	$	244.3	$	—