Fair Value Measurements (Tables)

6 Months Ended

Mar. 31, 2013

Fair Value Disclosures [Abstract]

Assets And Liabilities Measured At Fair Value On A Recurring Basis

Assets and Liabilities Measured at Fair Value on a Recurring Basis (in millions):

			Fair Value Measurements at Reporting Date Using
	Balance at March 31, 2013		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	$	1,223.2	$	1,223.2	$	—	$	—
Short-term investments:
Available-for-sale securities
Agency obligations	20.0		—		20.0		—
Commercial paper	59.0		—		59.0		—
Corporate debt securities	89.6		—		89.6		—
Government treasury securities	205.0		205.0		—		—
Certificates of deposit	37.6		—		37.6		—
Total available-for-sale securities	411.2		205.0		206.2		—
Trading securities	63.3		63.3		—		—
Total short-term investments	474.5		268.3		206.2		—
Short-term derivatives	14.4		—		14.4		—
Long-term investments:
Available-for-sale securities
Agency obligations	4.0		—		4.0		—
Corporate debt securities	24.0		—		24.0		—
Auction rate securities	13.9		—		—		13.9
Certificates of deposit	2.5		—		2.5		—
Total long-term investments	44.4		—		30.5		13.9
Long-term derivatives	7.5		—		7.5		—
Total	$	1,764.0	$	1,491.5	$	258.6	$	13.9
Liabilities:
Short-term derivatives	$	23.7	$	—	$	23.7	$	—
Long-term derivatives	1.1		—		1.1		—
Total	$	24.8	$	—	$	24.8	$	—

			Fair Value Measurements at Reporting Date Using
	Balance at September 30, 2012		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	$	1,188.6	$	1,188.6	$	—	$	—
Short-term investments:
Available-for-sale securities
Agency obligations	80.0		—		80.0		—
Commercial paper	103.9		—		103.9		—
Corporate debt securities	84.3		—		84.3		—
Government treasury securities	459.7		459.7		—		—
Certificates of deposit	62.9		—		62.9		—
Total available-for-sale securities	790.8		459.7		331.1		—
Trading securities	57.6		57.6		—		—
Total short-term investments	848.4		517.3		331.1		—
Short-term derivatives	9.5		—		9.5		—
Long-term investments:
Available-for-sale securities
Agency Obligations	14.0		—		14.0		—
Corporate debt securities	61.3		—		61.3		—
Auction rate securities	18.6		—		—		18.6
Certificates of deposit	22.1		—		22.1		—
Total long-term investments	116.0		—		97.4		18.6
Total	$	2,162.5	$	1,705.9	$	438.0	$	18.6
Liabilities:
Short-term derivatives	$	18.9	$	—	$	18.9	$	—
Long-term derivatives	3.0		—		3.0		—
Total	$	21.9	$	—	$	21.9	$	—