Debt (Components of Long Term Debt) (Parenthetical) (Detail)	Sep. 30, 2013 4% Notes, Due 2013	Sep. 30, 2013 4.875% Notes, Due 2013	Sep. 30, 2013 6.375% Notes, Due 2014	Jul. 31, 2013 6.375% Notes, Due 2014	Sep. 30, 2013 5.375% Notes, Due 2016	Sep. 30, 2013 1.875% notes, Due 2017	Sep. 30, 2013 1.75% Notes, Due 2018	Jun. 30, 2013 1.75% Notes, Due 2018	Sep. 30, 2013 8.625% Debentures, Due 2021	Sep. 30, 2013 3.25% Notes. Due 2022	Sep. 30, 2013 3.25% Notes, Due 2023	Jun. 30, 2013 3.25% Notes, Due 2023	Sep. 30, 2013 7.875% Debentures, Due 2023	Sep. 30, 2013 6.625% Debentures, Due 2028	Sep. 30, 2013 5.875% Notes, Due 2036
Debt Instrument [Line Items]
Debt instrument maturity year	2013	2013	2014		2016	2017	2018		2021	2022	2023		2023	2028	2036
Interest rate of debt	4.00%	4.875%	6.375%	6.375%	5.375%	1.875%	1.75%	1.75%	8.625%	3.25%	3.25%	3.25%	7.875%	6.625%	5.875%