TYCO INTERNATIONAL FINANCE S.A. (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Condensed Income Statements, Captions [Line Items]
Net sales	$ 30,172	$ 20,837	$ 17,100
Cost of sales	20,833	15,183	12,569
Gross Profit	9,339	5,654	4,531
Selling, General and Administrative Expense	(6,158)	(4,190)	(3,191)
Restructuring and impairment costs	(367)	(288)	(215)
Net Financing Charges	(496)	(289)	(274)
Equity income	240	174	80
Intercompany interest and fees	0	0
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	2,558	1,061	931
Income tax provision	705	197	71
Income (loss) from continuing operations	1,853	864	860
Loss from sale of intercompany investments	0
Loss from discontinued operations, net of tax (Note 4)	(34)	(1,516)	819
Net income (loss)	1,819	(652)	1,679
Income from continuing operations attributable to noncontrolling interests	199	132	46
Income from discontinued operations attributable to noncontrolling interests	9	84	70
Net income (loss)	1,611	(868)	$ 1,563
Consolidation, Eliminations [Member]
Condensed Income Statements, Captions [Line Items]
Net sales	0	0
Cost of sales	0	0
Gross Profit	0	0
Selling, General and Administrative Expense	0	0
Restructuring and impairment costs	0	0
Net Financing Charges	0	0
Equity income	(2,678)	2,762
Intercompany interest and fees	0	0
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	(2,678)	2,762
Income tax provision	0	0
Income (loss) from continuing operations	(2,678)	2,762
Loss from sale of intercompany investments	935
Loss from discontinued operations, net of tax (Note 4)	0	0
Net income (loss)	(1,743)	2,762
Income from continuing operations attributable to noncontrolling interests	0	0
Income from discontinued operations attributable to noncontrolling interests	0	0
Net income (loss)	(1,743)	2,762
Tyco Fire & Security Finance SCA
Condensed Income Statements, Captions [Line Items]
Net sales	0	0
Cost of sales	0	0
Gross Profit	0	0
Selling, General and Administrative Expense	0	(2)
Restructuring and impairment costs	0	0
Net Financing Charges	(1)	0
Equity income	874	(1,527)
Intercompany interest and fees	245	0
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	1,118	(1,529)
Income tax provision	0	0
Income (loss) from continuing operations	1,118	(1,529)
Loss from sale of intercompany investments	0
Loss from discontinued operations, net of tax (Note 4)	0	0
Net income (loss)	1,118	(1,529)
Income from continuing operations attributable to noncontrolling interests	0	0
Income from discontinued operations attributable to noncontrolling interests	0	0
Net income (loss)	1,118	(1,529)
Johnson Controls International plc
Condensed Income Statements, Captions [Line Items]
Net sales	0	0
Cost of sales	0	0
Gross Profit	0	0
Selling, General and Administrative Expense	(13)	(2)
Restructuring and impairment costs	0	0
Net Financing Charges	(179)	0
Equity income	1,839	(894)
Intercompany interest and fees	(27)	28
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	1,620	(868)
Income tax provision	9	0
Income (loss) from continuing operations	1,611	(868)
Loss from sale of intercompany investments	0
Loss from discontinued operations, net of tax (Note 4)	0	0
Net income (loss)	1,611	(868)
Income from continuing operations attributable to noncontrolling interests	0	0
Income from discontinued operations attributable to noncontrolling interests	0	0
Net income (loss)	1,611	(868)
Other Subsidiaries
Condensed Income Statements, Captions [Line Items]
Net sales	30,172	20,837
Cost of sales	20,833	15,183
Gross Profit	9,339	5,654
Selling, General and Administrative Expense	(6,145)	(4,185)
Restructuring and impairment costs	(367)	(288)
Net Financing Charges	(297)	(283)
Equity income	240	174
Intercompany interest and fees	(229)	(35)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	2,541	1,037
Income tax provision	696	197
Income (loss) from continuing operations	1,845	840
Loss from sale of intercompany investments	0
Loss from discontinued operations, net of tax (Note 4)	(34)	(1,516)
Net income (loss)	1,811	(676)
Income from continuing operations attributable to noncontrolling interests	199	132
Income from discontinued operations attributable to noncontrolling interests	9	84
Net income (loss)	1,603	(892)
Tyco International Finance S.A.
Condensed Income Statements, Captions [Line Items]
Net sales	0	0
Cost of sales	0	0
Gross Profit	0	0
Selling, General and Administrative Expense	0	(1)
Restructuring and impairment costs	0	0
Net Financing Charges	(19)	(6)
Equity income	(35)	(341)
Intercompany interest and fees	11	7
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	(43)	(341)
Income tax provision	0	0
Income (loss) from continuing operations	(43)	(341)
Loss from sale of intercompany investments	(935)
Loss from discontinued operations, net of tax (Note 4)	0	0
Net income (loss)	(978)	(341)
Income from continuing operations attributable to noncontrolling interests	0	0
Income from discontinued operations attributable to noncontrolling interests	0	0
Net income (loss)	$ (978)	$ (341)