Debt (Parenthetical) (Detail)	1 Months Ended	12 Months Ended		1 Months Ended	12 Months Ended		1 Months Ended	12 Months Ended		1 Months Ended	12 Months Ended	1 Months Ended	12 Months Ended	1 Months Ended	12 Months Ended	1 Months Ended	12 Months Ended
	Mar. 31, 2008 Senior Notes 4.63%	Apr. 28, 2012 Senior Notes 4.63%	Apr. 30, 2011 Senior Notes 4.63%	Mar. 31, 2008 Senior Notes 5.17%	Apr. 28, 2012 Senior Notes 5.17%	Apr. 30, 2011 Senior Notes 5.17%	Mar. 31, 2008 Senior Notes 5.75%	Apr. 28, 2012 Senior Notes 5.75%	Apr. 30, 2011 Senior Notes 5.75%	Dec. 31, 2011 Senior Notes 2.95%	Apr. 28, 2012 Senior Notes 2.95%	Dec. 31, 2011 Senior Notes 3.59%	Apr. 28, 2012 Senior Notes 3.59%	Dec. 31, 2011 Senior Notes 3.74%	Apr. 28, 2012 Senior Notes 3.74%	Mar. 31, 2008 Term Note Due Fiscal 2013	Apr. 28, 2012 Term Note Due Fiscal 2013	Apr. 30, 2011 Term Note Due Fiscal 2013
Debt Instrument [Line Items]
Fixed rate	4.63%	4.63%	4.63%	5.17%	5.17%	5.17%	5.75%	5.75%	5.75%	2.95%	2.95%	3.59%	3.59%	3.74%	3.74%
Variable rate, Libor																	1.25%	1.25%
Senior notes maturity date	2013	2013	2013	2015	2015	2015	2018	2018	2018	2018	2018	2021	2021	2023	2023	2013	2013	2013