Shareholders' Equity And Earnings Per Share (Schedule Of Earnings Per Share, Basic And Diluted) (Details) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended	3 Months Ended
	Oct. 26, 2011	Apr. 28, 2012	Apr. 30, 2011
Shareholders' Equity And Earnings Per Share [Line Items]
Stock repurchase program, authorized amount	$ 300
Shares repurchased		1,936,247
Shares repurchased, average price per share		$ 46.73
Net income		82.5	75.4
Basic weighted average number of shares in issue		85,500,000	86,100,000
Dilutive effect of share options		800,000	800,000
Diluted weighted average number of shares in issue		86,300,000	86,900,000
Earnings per share - basic		$ 0.96	$ 0.87
Earnings per share: diluted		$ 0.96	$ 0.87
Dividends payable, amount per share		$ 0.12
Dividends payable, amount		$ 10.2
Stock Options [Member]
Shareholders' Equity And Earnings Per Share [Line Items]
Anti-dilutive shares excluded from the calculation of earnings per share		160,135	335,117
Restricted Stock [Member]
Shareholders' Equity And Earnings Per Share [Line Items]
Effect of shares excluded from basic weighted average number of shares		1,686,503	532,187