Long-Term Debt - Summary of Long-Term Debt Carrying Values Including Unamortized Discounts and Premiums (Parenthetical) (Detail)	Feb. 28, 2013 5.875% Senior Notes, due 2014 [Member]	Feb. 28, 2013 3.875% Senior Note, due 2015 [Member]	Feb. 28, 2013 5.5% Senior Notes, due 2016 [Member]	Feb. 28, 2013 5.125% Senior Notes, due 2018 [Member]	Feb. 28, 2013 8.5% Senior Notes, due 2019 [Member]	Feb. 28, 2013 6.875% Senior Note, due 2021 [Member]	Apr. 30, 2012 6.875% Senior Note, due 2021 [Member]	Feb. 28, 2013 2.25% Euro Medium Term Notes, due 2022 [Member]	Jul. 13, 2012 2.25% Euro Medium Term Notes, due 2022 [Member]	Feb. 28, 2013 6.45% Senior Debentures, due 2027 [Member]	Feb. 28, 2013 5.125% Senior Notes, due 2023 [Member]	Feb. 28, 2013 6.50% Senior Notes, due 2043 [Member]	Feb. 28, 2013 3.875% Convertible Senior Debentures, due 2029 [Member]	Feb. 28, 2013 6.25% Senior Debentures, due 2036 [Member]
Debt Disclosure [Line Items]
Interest rates	5.875%	3.875%	5.50%	5.125%	8.50%	6.875%	6.875%	2.25%	2.25%	6.45%	5.125%	6.50%	3.875%	6.25%
Effective interest rates	6.00%	3.92%	5.57%	5.90%	8.31%	7.00%		6.22%		6.55%	5.16%	6.59%	7.74%	6.37%