Guarantor Financial Statements (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 25, 2016	Mar. 27, 2015	Mar. 25, 2016	Mar. 27, 2015	Sep. 25, 2015	Sep. 26, 2014
Statements of Operations
Net revenue	$ 2,331	$ 2,430	$ 4,707	$ 4,908
Cost of product sales	968	999	1,930	2,021
Cost of services	506	550	1,042	1,097
Selling, general and administrative expenses	602	648	1,175	1,300
Separation Transaction and Merger Costs	26	0	26	0
Restructuring and asset impairment charges, net	4	12	16	70
Operating income	225	221	518	420
Interest income	4	4	8	7
Interest expense	(22)	(25)	(46)	(49)
Other (expense) income, net	0	(1)	(165)	3
Equity in net income of subsidiaries	0	0	0	0
Intercompany interest and fees	0	0	0	0
Income from continuing operations before income taxes	207	199	315	381
Income tax expense	(63)	(18)	(99)	(37)
Income from continuing operations	144	181	216	344
Income (loss) from discontinued operations, net of income taxes	1	(16)	5	(18)
Net income	145	165	221	326
Less: noncontrolling interest in subsidiaries net loss	(1)	(2)	(1)	(3)
Net income attributable to Tyco ordinary shareholders	146	167	222	329
Statement of Comprehensive Income
Net income	145	165	221	326
Other comprehensive income (loss), net of tax
Foreign currency translation	44	(176)	1	(374)
Defined benefit and post retirement plans	3	4	8	9
Unrealized gain on marketable securities and derivative instruments, net of tax	2	0	3	0
Total other comprehensive income (loss), net of tax	49	(172)	12	(365)
Comprehensive (loss) income	194	(7)	233	(39)
Less: comprehensive loss attributable to noncontrolling interests	(1)	(2)	(1)	(3)
Comprehensive income (loss) attributable to Tyco ordinary shareholders	195	(5)	234	(36)
Cash Flows From Operating Activities:
Net cash provided by (used in) operating activities			313	262
Net cash used in discontinued operating activities			(11)	3
Cash Flows From Investing Activities:
Capital expenditures			(143)	(123)
Acquisition of businesses, net of cash acquired	(128)	(373)	(314)	(525)
Acquisition of dealer generated customer accounts and bulk account purchases			(11)	(8)
Net Increase in Intercompany Loans			0	0
Proceeds from Divestiture of Businesses, Net of Cash Divested			9	(1)
Sales and maturities of investments including restricted investments			8	279
Payments to Acquire Investments			(7)	(288)
Decrease (increase) in restricted cash			24	(39)
Other			1	2
Net cash used in investing activities			(433)	(703)
Net cash provided by (used in) discontinued investing activities			4	(15)
Cash Flows From Financing Activities:
Proceeds from issuance of short-term debt			2,498	0
Proceeds from Issuance of Long-term Debt			0	567
Proceeds from Issuance of Other Long-term Debt				567
Repayment of short-term debt			(2,098)	(1)
Repayment of current portion of long-term debt			(1,134)	0
Goodwill	4,460		4,460		$ 4,234	$ 4,119
Proceeds from exercise of share options			26	57
Dividends paid			(174)	(151)
Repurchase of ordinary shares by treasury			0	(417)
Net intercompany loan repayments			0	0
Transfer to discontinued operations			(7)	(12)
Payment of contingent consideration			(1)	(23)
Payments of Debt Issuance Costs			(23)	(4)
Other			(13)	(19)
Net cash used in financing activities			(926)	(3)
Net cash provided by discontinued financing activities			7	12
Effect of currency translation on cash			(10)	(16)
Net decrease in cash and cash equivalents			(1,056)	(460)
Cash and cash equivalents at beginning of period			1,401	892
Cash and cash equivalents at end of period	345		345
Tyco International plc
Statements of Operations
Selling, general and administrative expenses	2	2	4	5
Operating income	(2)	(2)	(4)	(5)
Interest income	0	0	0	0
Interest expense	0	0	0	0
Other (expense) income, net	0	0	0	0
Equity in net income of subsidiaries	145	152	163	295
Intercompany interest and fees	5	17	65	39
Income from continuing operations before income taxes	148	167	224	329
Income tax expense	(2)	0	(2)	0
Income from continuing operations	146	167	222	329
Income (loss) from discontinued operations, net of income taxes	0	0	0	0
Net income	146	167	222	329
Net income attributable to Tyco ordinary shareholders	146	167	222	329
Statement of Comprehensive Income
Net income	146	167	222	329
Other comprehensive income (loss), net of tax
Foreign currency translation	44	(176)	1	(374)
Defined benefit and post retirement plans	3	4	8	9
Unrealized gain on marketable securities and derivative instruments, net of tax	2		3
Total other comprehensive income (loss), net of tax	49	(172)	12	(365)
Comprehensive (loss) income	195	(5)	234	(36)
Less: comprehensive loss attributable to noncontrolling interests		0
Comprehensive income (loss) attributable to Tyco ordinary shareholders	$ 195	(5)	234	(36)
Cash Flows From Operating Activities:
Net cash provided by (used in) operating activities			160	20
Cash Flows From Investing Activities:
Proceeds from Divestiture of Businesses, Net of Cash Divested				0
Net cash used in investing activities			0	0
Cash Flows From Financing Activities:
Proceeds from exercise of share options			26	50
Dividends paid			(174)	(151)
Net intercompany loan repayments			0	83
Transfer to discontinued operations				0
Other			(12)	(2)
Net cash used in financing activities			$ (160)	(20)
Net cash provided by discontinued financing activities				0
Tyco International Finance S.A.
Condensed Financial Statements, Captions
Ownership Percentage of Subsidiary by Parent	100.00%		100.00%
Statements of Operations
Selling, general and administrative expenses	$ 1	0	$ 1	1
Separation Transaction and Merger Costs	10		10
Operating income	(11)	0	(11)	(1)
Interest expense	(22)	(24)	(45)	(48)
Other (expense) income, net	(1)	(2)	(166)	2
Equity in net income of subsidiaries	156	160	335	287
Intercompany interest and fees	22	24	47	51
Income from continuing operations before income taxes	144	158	160	291
Income tax expense	0	0	0	0
Income from continuing operations	144	158	160	291
Net income	144	158	160	291
Net income attributable to Tyco ordinary shareholders	144	158	160	291
Statement of Comprehensive Income
Net income	144	158	160	291
Other comprehensive income (loss), net of tax
Foreign currency translation	(13)	16	1	15
Defined benefit and post retirement plans		0
Unrealized gain on marketable securities and derivative instruments, net of tax	0		0
Total other comprehensive income (loss), net of tax	(13)	16	1	15
Comprehensive (loss) income	131	174	161	306
Less: comprehensive loss attributable to noncontrolling interests		0
Comprehensive income (loss) attributable to Tyco ordinary shareholders	131	174	161	306
Cash Flows From Operating Activities:
Net cash provided by (used in) operating activities			701	(504)
Cash Flows From Investing Activities:
Net Increase in Intercompany Loans			28	(59)
Proceeds from Divestiture of Businesses, Net of Cash Divested				0
Sales and maturities of investments including restricted investments			5
Payments to Acquire Investments			0
Net cash used in investing activities			33	(59)
Cash Flows From Financing Activities:
Proceeds from issuance of short-term debt			2,498
Proceeds from Issuance of Other Long-term Debt				567
Repayment of short-term debt			(2,098)	0
Repayment of current portion of long-term debt			(1,134)
Transfer to discontinued operations				0
Payments of Debt Issuance Costs				(4)
Other			0
Net cash used in financing activities			(734)	563
Other Subsidiaries
Statements of Operations
Net revenue	2,331	2,430	4,707	4,908
Cost of product sales	968	999	1,930	2,021
Cost of services	506	550	1,042	1,097
Selling, general and administrative expenses	599	646	1,170	1,294
Separation Transaction and Merger Costs	16		16
Restructuring and asset impairment charges, net	4	12	16	70
Operating income	238	223	533	426
Interest income	4	4	8	7
Interest expense	0	(1)	(1)	(1)
Other (expense) income, net	1	1	1	1
Intercompany interest and fees	(27)	(41)	(112)	(90)
Income from continuing operations before income taxes	216	186	429	343
Income tax expense	(61)	(18)	(97)	(37)
Income from continuing operations	155	168	332	306
Income (loss) from discontinued operations, net of income taxes	1	(16)	5	(18)
Net income	156	152	337	288
Less: noncontrolling interest in subsidiaries net loss	(1)	(2)	(1)	(3)
Net income attributable to Tyco ordinary shareholders	157	154	338	291
Statement of Comprehensive Income
Net income	156	152	337	288
Other comprehensive income (loss), net of tax
Foreign currency translation	57	(192)	0	(389)
Defined benefit and post retirement plans	3	4	8	9
Unrealized gain on marketable securities and derivative instruments, net of tax	2		3
Total other comprehensive income (loss), net of tax	62	(188)	11	(380)
Comprehensive (loss) income	218	(36)	348	(92)
Less: comprehensive loss attributable to noncontrolling interests	(1)	(2)	(1)	(3)
Comprehensive income (loss) attributable to Tyco ordinary shareholders	219	(34)	349	(89)
Cash Flows From Operating Activities:
Net cash provided by (used in) operating activities			(548)	746
Net cash used in discontinued operating activities			(11)	3
Cash Flows From Investing Activities:
Capital expenditures			(143)	(123)
Acquisition of businesses, net of cash acquired			(314)	(525)
Acquisition of dealer generated customer accounts and bulk account purchases			(11)	(8)
Net Increase in Intercompany Loans			0	0
Proceeds from Divestiture of Businesses, Net of Cash Divested			9	(1)
Sales and maturities of investments including restricted investments			3	279
Payments to Acquire Investments			(7)	(288)
Decrease (increase) in restricted cash			24	(39)
Other			1	2
Net cash used in investing activities			(438)	(703)
Net cash provided by (used in) discontinued investing activities			4	(15)
Cash Flows From Financing Activities:
Proceeds from issuance of short-term debt			0
Repayment of short-term debt			0	(1)
Goodwill	4,460		4,460		$ 4,234
Proceeds from exercise of share options			0	7
Dividends paid				0
Repurchase of ordinary shares by treasury				(417)
Net intercompany loan repayments			(28)	(24)
Transfer to discontinued operations			(7)	(12)
Payment of contingent consideration			(1)	(23)
Payments of Debt Issuance Costs			(23)
Other			(1)	(17)
Net cash used in financing activities			(60)	(487)
Net cash provided by discontinued financing activities			7	12
Effect of currency translation on cash			(10)	(16)
Net decrease in cash and cash equivalents			(1,056)	(460)
Cash and cash equivalents at beginning of period			1,401	892
Cash and cash equivalents at end of period	345		345
Consolidating Adjustments
Statements of Operations
Equity in net income of subsidiaries	(445)	(470)	(658)	(873)
Intercompany interest and fees	0	0	0	0
Income from continuing operations before income taxes	(445)	(470)	(658)	(873)
Income from continuing operations	(445)	(470)	(658)	(873)
Income (loss) from discontinued operations, net of income taxes	0	0	0	0
Net income	(445)	(470)	(658)	(873)
Net income attributable to Tyco ordinary shareholders	(445)	(470)	(658)	(873)
Statement of Comprehensive Income
Net income	(445)	(470)	(658)	(873)
Other comprehensive income (loss), net of tax
Foreign currency translation	(44)	176	(1)	374
Defined benefit and post retirement plans	(3)	(4)	(8)	(9)
Unrealized gain on marketable securities and derivative instruments, net of tax	(2)		(3)
Total other comprehensive income (loss), net of tax	(49)	172	(12)	365
Comprehensive (loss) income	(494)	(298)	(670)	(508)
Less: comprehensive loss attributable to noncontrolling interests		0
Comprehensive income (loss) attributable to Tyco ordinary shareholders	(494)	(298)	(670)	(508)
Cash Flows From Investing Activities:
Net Increase in Intercompany Loans			(28)	59
Proceeds from Divestiture of Businesses, Net of Cash Divested				0
Net cash used in investing activities			(28)	59
Cash Flows From Financing Activities:
Net intercompany loan repayments			28	(59)
Other				0
Net cash used in financing activities			28	(59)
Net cash provided by discontinued financing activities			0	0
Effect of currency translation on cash				0
Tyco Fire & Security Finance SCA [Member]
Statements of Operations
Selling, general and administrative expenses	0	0	0	0
Operating income	0	0	0	0
Interest income	0	0	0	0
Interest expense	0	0	0	0
Other (expense) income, net	0	0	0	0
Equity in net income of subsidiaries	144	158	160	291
Intercompany interest and fees	0	0	0	0
Income from continuing operations before income taxes	144	158	160	291
Income tax expense	0	0	0	0
Income from continuing operations	144	158	160	291
Income (loss) from discontinued operations, net of income taxes	0	0	0	0
Net income	144	158	160	291
Net income attributable to Tyco ordinary shareholders	144	158	160	291
Statement of Comprehensive Income
Net income	144	158	160	291
Other comprehensive income (loss), net of tax
Foreign currency translation	0	0	0	0
Defined benefit and post retirement plans	0	0	0	0
Unrealized gain on marketable securities and derivative instruments, net of tax	0		0
Total other comprehensive income (loss), net of tax	0	0	0	0
Comprehensive (loss) income	144	158	160	291
Less: comprehensive loss attributable to noncontrolling interests		0
Comprehensive income (loss) attributable to Tyco ordinary shareholders	$ 144	$ 158	$ 160	$ 291