Earnings Per Share - Earnings Per Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2012
Income from continuing operations available to common shares (in Dollars)	$ 247.9		$ 272.7		$ 249.7
Basic weighted average shares outstanding (in shares)	248.6		262.6		288.8
Dilutive effect of non-participating share-based awards (in shares)	1.9		2.6		1.6
Diluted weighted average common shares outstanding (in shares)	250.5		265.2		290.4
Basic EPS from continuing operations (in Dollars per share)	$ 1.00		$ 1.04		$ 0.86
Diluted EPS from continuing operations (in Dollars per share)	$ 0.99		$ 1.03		$ 0.86
Weighted average shares excluded from diluted EPS because the effect would be anti-dilutive:
Shares Repurchased including net shares, total	12.3	[1]	12.8	[1]	32.9	[1]
Shares Repurchased including net shares average price per share	$ 17.25		$ 17.71		$ 14.23
Shares Repurchased Including Net shares Aggregate Payment	211.6		190.5		475.2
Remaining Authorization	$ 209.7
Share Based Awards [Member]
Weighted average shares excluded from diluted EPS because the effect would be anti-dilutive:
Weighted average shares excluded from diluted EPS (in shares)	6.5		8.2		11.3
Notes [Member]
Weighted average shares excluded from diluted EPS because the effect would be anti-dilutive:
Weighted average shares excluded from diluted EPS (in shares)	0	[2]	42.6	[2]	42.6	[2]
Note Hedges [Member]
Weighted average shares excluded from diluted EPS because the effect would be anti-dilutive:
Weighted average shares excluded from diluted EPS (in shares)	0		(42.6)		(42.6)
Warrant [Member]
Weighted average shares excluded from diluted EPS because the effect would be anti-dilutive:
Weighted average shares excluded from diluted EPS (in shares)	42.6		42.6		42.6

[1] Including net shares tendered by employees at vesting for tax withholding obligations

[2] Excluded because the conversion price and exercise price exceeded the average market price of our common stock