Stock Plans (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Deferred Compensation Plan
Compensation expense related to employer contributions under defined contribution plans, including the DCP	$ 14.6	$ 15.9	$ 17.2
Stock options
Stock Incentive Plans
Securities available for future issuance (in shares)	17,600,000
Expiration term of unexercised options	7 years
Compensation expense
Recognized compensation expense	0.3	2.4	4.6
Unrecognized compensation expense	$ 0.2
Period of recognition of unrecognized compensation expense	3 years
Weighted average assumptions used to determine fair value of options granted to employees
Dividend yield (as a percent)			0.00%
Expected volatility (as a percent)			38.60%
Risk-free interest rate (as a percent)			1.50%
Term			4 years 6 months
Weighted average grant-date fair value of stock options granted (in dollars per share)			$ 9.43
Number of Options
Balance at the beginning of the period (in shares)	2,500,000	2,900,000	3,100,000
Granted (in shares)			400,000
Exercised (in shares)	(800,000)	(400,000)	(500,000)
Cancelled (in shares)	(100,000)		(100,000)
Balance at the end of the period (in shares)	1,600,000	2,500,000	2,900,000
Exercisable at the end of the period (in shares)	1,400,000	2,100,000	2,100,000
Stock options, Weighted Average Exercise Price
Balance at the beginning of the period (in dollars per share)	$ 22.81	$ 21.38	$ 19.09
Granted (in dollars per share)			$ 27.65
Exercised (in dollars per share)	$ 18.31	$ 11.40	$ 12.28
Cancelled (in dollars per share)	$ 26.83	$ 26.23	$ 23.91
Balance at the end of the period (in dollars per share)	$ 24.73	$ 22.81	$ 21.38
Exercisable at the end of the period (in dollars per share)	$ 24.51	$ 22.07	$ 19.55