Long-Term Debt - 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
	Mar. 31, 2008 Senior Notes 5.17% [Member]	Apr. 26, 2014 Senior Notes 5.17% [Member]	Apr. 27, 2013 Senior Notes 5.17% [Member]	Mar. 31, 2008 Senior Notes 5.75% [Member]	Apr. 26, 2014 Senior Notes 5.75% [Member]	Apr. 27, 2013 Senior Notes 5.75% [Member]	Dec. 31, 2011 Senior Notes 2.95% [Member]	Apr. 26, 2014 Senior Notes 2.95% [Member]	Apr. 27, 2013 Senior Notes 2.95% [Member]	Dec. 31, 2011 Senior Notes 3.59% [Member]	Apr. 26, 2014 Senior Notes 3.59% [Member]	Apr. 27, 2013 Senior Notes 3.59% [Member]	Dec. 31, 2011 Senior Notes 3.74% [Member]	Apr. 26, 2014 Senior Notes 3.74% [Member]	Apr. 27, 2013 Senior Notes 3.74% [Member]
Debt Instrument [Line Items]
Fixed rate	5.17%	5.17%	5.17%	5.75%	5.75%	5.75%	2.95%	2.95%	2.95%	3.59%	3.59%	3.59%	3.74%	3.74%	3.74%
Senior notes maturity date	2015	2015	2015	2018	2018	2018	2019	2019	2019	2022	2022	2022	2024	2024	2024