Condensed Financial Information of Registrant (Parent Company) (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2010
Condensed Financial Statements, Captions [Line Items]
NET CASH PROVIDED BY OPERATING ACTIVITIES	$ 707.7		$ 554.7		$ 598.8
CASH FLOWS FROM INVESTING ACTIVITIES:
Net cash used by investing activities	(1,904.5)		(415.4)		(399.3)
CASH FLOWS FROM FINANCING ACTIVITIES:
Payment of dividends on Common Stock	(119.1)		(113.8)		(98.6)
Issuance of Common Stock	23.2		27.3		27.5
Net cash provided (used) by financing activities	1,278.5		(152.1)		(213.6)
Cash and cash equivalents increase (decrease)	81.4		(22.2)		(19.4)
Cash and cash equivalents:
End of year	319.9		238.5		260.7
Beginning of year	238.5		260.7		280.1
Increase (decrease)	81.4		(22.2)		(19.4)
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
NET CASH PROVIDED BY OPERATING ACTIVITIES	158.3	[1]	201.6	[1]	173.0	[1]
CASH FLOWS FROM INVESTING ACTIVITIES:
Net investments in unconsolidated subsidiaries	(54.4)		(119.4)		(106.6)
Net cash used by investing activities	(54.4)		(119.4)		(106.6)
CASH FLOWS FROM FINANCING ACTIVITIES:
Payment of dividends on Common Stock	(119.1)		(113.8)		(98.6)
Issuance of Common Stock	16.7		31.0		31.8
Net cash provided (used) by financing activities	(102.4)		(82.8)		(66.8)
Cash and cash equivalents increase (decrease)	1.5		(0.6)		(0.4)
Cash and cash equivalents:
End of year	1.9		0.4		1.0
Beginning of year	0.4		1.0		1.4
Increase (decrease)	$ 1.5		$ (0.6)		$ (0.4)

[1] Includes dividends received from unconsolidated subsidiaries of $156.0, $188.9 and $172.8, for the years ended September 30, 2012, 2011 and 2010, respectively.