Debt (Details) (USD $)	1 Months Ended	3 Months Ended	9 Months Ended			1 Months Ended	3 Months Ended												1 Months Ended										1 Months Ended						1 Months Ended				1 Months Ended			1 Months Ended
	Jan. 31, 2011	Jun. 29, 2012	Jun. 29, 2012	Jun. 24, 2011	Sep. 30, 2011	Jun. 29, 2012 ADT Corporation D	Jun. 29, 2012 ADT Corporation	Jun. 22, 2012 ADT Corporation	Jun. 29, 2012 Total	Sep. 30, 2011 Total	Jun. 29, 2012 Carrying amount	Sep. 30, 2011 Carrying amount	Jun. 29, 2012 6.0% public notes due 2013	Sep. 30, 2011 6.0% public notes due 2013	Jun. 29, 2012 4.125% public notes due 2014	Sep. 30, 2011 4.125% public notes due 2014	Jun. 29, 2012 3.375% public notes due 2015	Sep. 30, 2011 3.375% public notes due 2015	Jan. 31, 2011 3.75% public notes due 2018	Jun. 29, 2012 3.75% public notes due 2018	Sep. 30, 2011 3.75% public notes due 2018	Jan. 12, 2011 3.75% public notes due 2018	Jun. 29, 2012 8.5% public notes due 2019	Sep. 30, 2011 8.5% public notes due 2019	Jun. 29, 2012 7.0% public notes due 2019	Sep. 30, 2011 7.0% public notes due 2019	Jun. 29, 2012 6.875% public notes due 2021	Sep. 30, 2011 6.875% public notes due 2021	Jan. 31, 2011 4.625% public notes due 2023	Jun. 29, 2012 4.625% public notes due 2023	Sep. 30, 2011 4.625% public notes due 2023	Jan. 12, 2011 4.625% public notes due 2023	Jun. 29, 2012 Other	Sep. 30, 2011 Other	Apr. 30, 2012 Revolving senior credit facility due 2007 Y	Jun. 22, 2012 Revolving senior credit facility due 2007	Apr. 25, 2012 Revolving senior credit facility due 2007	Jan. 12, 2011 6.75% public notes due 2011	Jun. 29, 2012 Revolving senior credit facility due 2012 Y	Jun. 22, 2012 Revolving senior credit facility due 2012	Jun. 22, 2012 Revolving senior credit facility due 2011	Jun. 29, 2012 Senior Unsecured Credit Agreement ADT Corporation Y	Jun. 22, 2012 Senior Unsecured Credit Agreement ADT Corporation
Debt:
Debt		$ 4,165,000,000	$ 4,165,000,000		$ 4,148,000,000								$ 656,000,000	$ 655,000,000	$ 499,000,000	$ 499,000,000	$ 499,000,000	$ 499,000,000		$ 249,000,000	$ 249,000,000		$ 750,000,000	$ 750,000,000	$ 430,000,000	$ 431,000,000	$ 714,000,000	$ 715,000,000		$ 248,000,000	$ 248,000,000		$ 120,000,000	$ 102,000,000
Less current portion		16,000,000	16,000,000		2,000,000																												16,000,000	2,000,000
Long-term debt		4,149,000,000	4,149,000,000		4,146,000,000
Debt stated interest rate (as a percent)													6.00%	6.00%	4.125%	4.125%	3.375%	3.375%		3.75%	3.75%	3.75%	8.50%	8.50%	7.00%	7.00%	6.875%	6.875%		4.625%	4.625%	4.625%						6.75%
Debt instrument, fair value									4,789,000,000	4,689,000,000	4,045,000,000	4,046,000,000
Fair value of debt which is actively traded		4,789,000,000	4,789,000,000		4,689,000,000
Line of credit, current available commitment						250,000,000	250,000,000	250,000,000
Description of variable interest rate basis			LIBOR
Available line of credit under revolving credit agreement		1,750,000,000	1,750,000,000																																	654,000,000	750,000,000			1,000,000,000			750,000,000
Available line of credit under revolving credit agreement, after amendment																																				500,000,000	654,000,000
Additional debt issued						2,500,000,000													250,000,000										250,000,000
Net proceeds of received from issuance of debt	494,000,000			497,000,000
Payment of debt issuance costs																			1,000,000										2,000,000
Debt discount																						1,000,000										2,000,000
Revolving credit line, term (in years)																																			5				5			5
Term of bridge loan facility (in days)						364
Bridge facility								2,250,000,000
Revolving credit commitments expired																																									750,000,000
Accrued interest costs written off		$ 3,000,000	$ 3,000,000				$ 3,000,000