Schedule IV - Reinsurance Schedule IV - Reinsurance (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Gross Amount, life insurance in force	$ 2,785.6	$ 2,596.7	$ 2,436.3
Ceded to other companies, life insurance in force	(2,014.3)	(1,965.4)	(1,929.0)
Assumed from other companies, life insurance in force	16.4	17.3	22.8
Net Amount, life insurance in force	787.7	648.6	530.1
Percentage of amount assumed to net, life insurance in force	2.08%	2.67%	4.30%
Gross Amount, premiums and other considerations	409.3	414.7	415.9
Ceded to other companies, premiums and other considerations	(317.5)	(328.2)	(369.5)
Assumed from other companies, premiums and other considerations	35.9	32.8	47.2
Total Premiums and Other Considerations, net	127.7	119.3	93.6
Net Amount, premiums and other considerations	56.6	58.8	55.3
Percentage of amount assumed to net, premiums and other considerations	28.10%	27.49%	50.43%
Life Insurance Product Line
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Gross Amount, premiums and other considerations	266.8	279.2	298.0
Ceded to other companies, premiums and other considerations	(246.1)	(253.2)	(289.9)
Assumed from other companies, premiums and other considerations	35.9	32.8	47.2
Net Amount, premiums and other considerations	56.6	58.8	55.3
Percentage of amount assumed to net, premiums and other considerations	63.40%	55.78%	85.40%
Annuity product line
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Gross Amount, premiums and other considerations	142.5	135.5	117.9
Ceded to other companies, premiums and other considerations	(71.4)	(75.0)	(79.6)
Assumed from other companies, premiums and other considerations	0	0	0
Net Amount, premiums and other considerations	$ 71.1	$ 60.5	$ 38.3
Percentage of amount assumed to net, premiums and other considerations	0.00%	0.00%	0.00%