Shareholders' equity (Share repurchase program textuals) (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	1 Months Ended	12 Months Ended
	Jul. 31, 2015	Jun. 27, 2015	Jun. 28, 2014	Nov. 30, 2014	Aug. 31, 2012
Shareholders' equity
Authorized repurchase of common stock under Share Repurchase Program				$ 1,000,000	$ 1,000,000
Shares repurchased during period (in shares)	1.6	4.0
Average market price per share repurchased during period (in dollars per share)		$ 40.84
Cost of repurchase	$ 64,200	$ 163,400
Aggregate number of shares repurchased since inception (in shares)		22.1
Aggregate cost of shares repurchased since inception		$ 697,500
Remaining authorized repurchase amount		$ 302,500
Cash dividends paid per common share		$ 0.64	$ 0.60
Dividends paid on common stock		$ 87,330	$ 82,755