Legal proceedings and contingencies (Details) - USD ($) $ in Millions	3 Months Ended
	Oct. 02, 2015	Dec. 28, 2012
Broadcast Communications [Member]
Loss Contingencies [Line Items]
Asset Sale Agreement		$ 225
Asset Sale Agreement, cash		160
Asset Sale Agreement, promissory note		15
Asset Sale Agreement, earnout		$ 50
Low-End Range Of Possible Outcomes In Arbitration	$ 0
High-End Range of Possible Outcomes In Arbitration	67
Passaic River Alaska [Member] | Exelis [Member]
Loss Contingencies [Line Items]
Estimated cost for all participating parities of remedial alternatives low range	400
Estimated cost for all participating parties of remedial alternatives high range	3,200
Estimated cost for all participating parties of EPA's preferred alternative	$ 1,700