Marketable Securities (Tables)

12 Months Ended

Sep. 30, 2011

Marketable Securities [Abstract]

Marketable Securities

	September 30, 2011
			Gross		Gross
	Amortized		Unrealized		Unrealized			Fair
	Cost		Gains		Losses			Value
			(In millions)
Type of security:
U.S. Treasury securities	$	16.3	$	—	$	—		$	16.3
Obligations of U.S. government agencies		73.7		0.1		—			73.8
Corporate debt securities issued under the FDIC Temporary Liquidity Guarantee Program		103.7		0.1		—			103.8
Corporate debt securities		98.8		—		(0.1	)		98.7
Total debt securities		292.5		0.2		(0.1	)		292.6
Certificates of deposit		5.0		—		—			5.0
Total marketable securities, available-for-sale	$	297.5	$	0.2	$	(0.1	)	$	297.6

	September 30, 2010
			Gross		Gross
	Amortized		Unrealized		Unrealized		Fair
	Cost		Gains		Losses		Value
			(In millions)
Type of security:
U.S. Treasury securities	$	1.0	$	—	$	—	$	1.0
Obligations of U.S. government agencies		131.0		0.2		—		131.2
Corporate debt securities issued under the FDIC Temporary Liquidity Guarantee Program		100.9		0.1		—		101.0
Corporate debt securities		39.9		—		—		39.9
Foreign government securities		14.6		—		—		14.6
Total debt securities		287.4		0.3		—		287.7
Certificates of deposit		10.0		—		—		10.0
Total marketable securities, available-for-sale	$	297.4	$	0.3	$	—	$	297.7