Investments - Schedule of Allowance for Credit Losses (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended		15 Months Ended
	Jun. 30, 2013	Jun. 30, 2013	Jul. 01, 2012	Jul. 01, 2013	Dec. 30, 2012	Jul. 31, 2012	Jan. 01, 2012
Investments, Debt and Equity Securities [Abstract]
Document Period End Date		Jun. 30, 2013
Allowance for credit losses:
Balance at beginning of period		$ 1.4			$ 2.8	$ 0.6	$ 0.2
Provision for credit losses	0.3	1.7	0.6	0.4
Charge-offs
Recoveries
Balance at end of period	$ 3.1	$ 3.1			$ 2.8	$ 0.6	$ 0.2