Reinsurance - Effect of Reinsurance on Premiums Earned, Benefits Incurred and Reserve Changes (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
Mar. 31, 2013	Apr. 01, 2012	Mar. 31, 2013	Apr. 01, 2012
Insurance Premiums:
Direct	$ 70.0	$ 75.0	$ 142.4	$ 151.2
Assumed	3.3	12.1	15.4	24.3
Ceded	(59.2)	(73.8)	(129.9)	(145.4)
Net	14.1	13.3	27.9	30.1
Benefits and Other Changes in Insurance Policy Reserves:
Direct	289.3	287.1	428.9	524.8
Assumed	1.0	9.5	7.5	18.0
Ceded	(49.4)	(54.8)	(111.9)	(124.1)
Net	$ 240.9	$ 241.8	$ 324.5	$ 418.7

Premiums earned for all life insurance assumed from other insurers as a result of reinsurance arrangements.

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Premiums assumed and earned by another insurer as a result of reinsurance arrangements.

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Premiums earned directly for all life insurance before adding contracts assumed from other insurers or subtracting any amounts assumed by other insurers.

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Premiums recognized as revenue in the period earned on all life insurance and reinsurance contracts after subtracting any amounts ceded to another insurer.

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The amount of the provision for the period for claims and benefits incurred on contract risks assumed from other (ceding) insurers under reinsurance arrangements.

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The reduction in the amount of the provision for the period for claims and benefits incurred on contract risks ceded to other insurers under reinsurance arrangements.

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The net amount of the provision for the period for claims and benefits incurred on contracts directly written, assumed, and ceded.

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The amount of the provision for the period for claims and benefits incurred on contracts acquired by the insurer during the period in other than reinsurance arrangements.

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