Fair Value Measurements (Tables)

3 Months Ended

Dec. 30, 2018

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Assets And Liabilities Measured At Fair Value On A Recurring Basis

			Fair Value Measurements at Reporting Date Using
	Balance at December 30, 2018		Quoted Prices in Active Markets for  Identical Assets (Level 1)		Significant  Other Observable  Inputs (Level 2)		Significant Unobservable  Inputs (Level 3)
Assets:
Cash and cash equivalents	$	4,761.6	$	4,761.6	$	—	$	—
Short-term investments:
Available-for-sale securities
Commercial paper	10.5		—		10.5		—
Corporate debt securities	119.0		—		119.0		—
Foreign government obligations	3.6		—		3.6		—
U.S. government treasury securities	25.0		25.0		—		—
Mortgage and other asset-backed securities	12.6		—		12.6		—
Certificates of deposit	3.0		—		3.0		—
Total available-for-sale securities	173.7		25.0		148.7		—
Trading securities	56.5		56.5		—		—
Total short-term investments	230.2		81.5		148.7		—
Prepaid expenses and other current assets:
Derivative assets	25.1		—		25.1		—
Long-term investments:
Available-for-sale securities
Agency obligations	6.0		—		6.0		—
Corporate debt securities	121.7		—		121.7		—
Auction rate securities	5.7		—		—		5.7
U.S. government treasury securities	114.6		114.6		—		—
State and local government obligations	4.8		—		4.8		—
Mortgage and other asset-backed securities	12.2		—		12.2		—
Total long-term investments	265.0		114.6		144.7		5.7
Other long-term assets:
Derivative assets	9.5		—		9.5		—
Total assets	$	5,291.4	$	4,957.7	$	328.0	$	5.7
Liabilities:
Accrued liabilities:
Derivative liabilities	$	19.4	$	2.1	$	17.3	$	—
Other long-term liabilities:
Derivative liabilities	51.8		—		51.8		—
Total liabilities	$	71.2	$	2.1	$	69.1	$	—

			Fair Value Measurements at Reporting Date Using
	Balance at September 30, 2018		Quoted Prices in Active Markets for  Identical Assets (Level 1)		Significant  Other Observable  Inputs (Level 2)		Significant Unobservable  Inputs (Level 3)
Assets:
Cash and cash equivalents	$	8,756.3	$	8,756.3	$	—	$	—
Short-term investments:
Available-for-sale securities
Commercial paper	8.4		—		8.4		—
Corporate debt securities	91.8		—		91.8		—
Mortgage and other asset-backed securities	6.0		—		6.0		—
Total available-for-sale securities	106.2		—		106.2		—
Trading securities	75.3		75.3		—		—
Total short-term investments	181.5		75.3		106.2		—
Prepaid expenses and other current assets:
Derivative assets	24.5		1.2		23.3		—
Long-term investments:
Available-for-sale securities
Agency obligations	5.9		—		5.9		—
Corporate debt securities	114.5		—		114.5		—
Auction rate securities	5.9		—		—		5.9
Foreign government obligations	3.6		—		3.6		—
U.S. government treasury securities	108.1		108.1		—		—
State and local government obligations	4.8		—		4.8		—
Mortgage and other asset-backed securities	24.9		—		24.9		—
Total long-term investments	267.7		108.1		153.7		5.9
Other long-term assets:
Derivative assets	10.4		—		10.4		—
Total assets	$	9,240.4	$	8,940.9	$	293.6	$	5.9
Liabilities:
Accrued liabilities:
Derivative liabilities	$	6.5	$	0.4	$	6.1	$	—
Other long-term liabilities:
Derivative liabilities	43.5		—		43.5		—
Total liabilities	$	50.0	$	0.4	$	49.6	$	—