Divestitures (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Mar. 25, 2016	Dec. 25, 2015	Sep. 25, 2015	Mar. 27, 2015	Mar. 25, 2016	Mar. 27, 2015
Significant Acquisitions and Disposals [Line Items]
Pre-tax loss from discontinued operations	$ (1)			$ (6)	$ (2)	$ (9)
Provision for cumulated translation losses included in pre-tax loss for write-down to fair value	24
Pre-Tax gain resulting from transfer of Tyco's equity interest in joint venture to Pentair Ltd.		$ 17
Selling, General and Administrative Expenses
Significant Acquisitions and Disposals [Line Items]
loss (gain) on divestitures	17			$ 22	69	$ 23
Selling, General and Administrative Expenses | Australia Fire and Security [Member]
Significant Acquisitions and Disposals [Line Items]
Provision for cumulated translation losses included in pre-tax loss for write-down to fair value		24			31
loss (gain) on divestitures	$ 18				$ 75
Disposal Group, Not Discontinued Operation, Loss (Gain) on Write-down		$ 57
Selling, General and Administrative Expenses | Shurjoint [Member]
Significant Acquisitions and Disposals [Line Items]
loss (gain) on divestitures			$ 17