Summary of Significant Accounting Policies (Details 3) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 30, 2012	Jan. 01, 2012	Jan. 02, 2011
Change in Accounting Estimate [Line Items]
Favorable effect of change in accounting estimate on operating income	$ 18.0	$ 4.7	$ 3.5
Unfavorable effect of change in accounting estimate on operating income	19.2	4.4	3.2
Contracts Accounted for under Percentage of Completion [Member]
Change in Accounting Estimate [Line Items]
Net effect of change in accounting estimate on operating income	$ 1.2	$ 0.3