Significant Restructuring Costs - Additional Information (Detail) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended			45 Months Ended
	Jun. 30, 2016 USD ($) Plant Employees	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($) Plant Employees	Jun. 30, 2015 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2013 USD ($)	Jun. 30, 2016 USD ($) Plant Employees
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ (102)	$ 0	$ (331)	$ 0
Number of employees to be severed | Employees								17,800
Number of employees severed | Employees	11,200		11,200					11,200
Number of plants to be closed | Plant								27
Plants closed | Plant	11		11					11
Corporate Segment
Restructuring Cost and Reserve [Line Items]
Number of employees to be severed | Employees								100
Automotive Experience
Restructuring Cost and Reserve [Line Items]
Number of employees to be severed | Employees								10,700
Number of plants to be closed | Plant								20
Power Solutions
Restructuring Cost and Reserve [Line Items]
Number of employees to be severed | Employees								900
Building Efficiency
Restructuring Cost and Reserve [Line Items]
Number of employees to be severed | Employees								6,100
Number of plants to be closed | Plant								7
2015 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			$ (72)		$ 0
Restructuring charges					(397)
Restructuring Reserve, Settled without Cash			0		183
Restructuring Reserve	$ 142		142		214			$ 142
2015 Restructuring Plan [Domain] | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges					(397)
2014 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			(53)		(70)	$ (8)
Restructuring charges						(377)
Restructuring Reserve, Settled without Cash			2		13	187
Restructuring Reserve	44		44		99	182		44
2014 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges						(324)
2014 Restructuring Plan | Automotive Experience Electronics | Discontinued Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges						(53)
2013 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			(39)		(113)	(147)	$ (26)
Restructuring charges							(985)
Restructuring Reserve, Settled without Cash			1		10	11	586
Restructuring Reserve	28		28		68	191	342	28
2013 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges							(903)
2013 Restructuring Plan | Discontinued Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges							(82)
2013 Restructuring Plan | Transfer From Held for Sale [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Accrual Adjustment						31
2013 Restructuring Plan | Global Workplace Solutions | Discontinued Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges							(54)
2013 Restructuring Plan | Automotive Experience Electronics | Discontinued Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges							(28)
Building Efficiency Systems and Service North America | 2015 Restructuring Plan [Domain] | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges					(3)
Building Efficiency Systems and Service North America | 2014 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges						(12)
Building Efficiency Systems and Service North America | 2013 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges							(35)
Building Efficiency Products North America | 2015 Restructuring Plan [Domain] | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges					(11)
Building Efficiency Products North America | 2014 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges						(7)
Building Efficiency Products North America | 2013 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges							(28)
Automotive Experience Interiors | 2014 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges						(130)
Automotive Experience Interiors | 2013 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges							(560)
Automotive Experience Seating [Member] | 2015 Restructuring Plan [Domain] | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges					(182)
Automotive Experience Seating [Member] | 2014 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges						(29)
Automotive Experience Seating [Member] | 2013 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges							(152)
Building Efficiency Rest of World [Member] | 2015 Restructuring Plan [Domain] | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges					(13)
Building Efficiency Rest of World [Member] | 2014 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges						(119)
Building Efficiency Rest of World [Member] | 2013 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges							(70)
Power Solutions | 2015 Restructuring Plan [Domain] | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges					(11)
Power Solutions | 2014 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges						(16)
Power Solutions | 2013 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges							(36)
Corporate Segment | 2015 Restructuring Plan [Domain] | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges					(166)
Corporate Segment | 2014 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges						(7)
Corporate Segment | 2013 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges							(17)
Building Efficiency Asia | 2015 Restructuring Plan [Domain] | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges					(11)
Building Efficiency Asia | 2014 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges						(4)
Building Efficiency Asia | 2013 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Restructuring charges							(5)
Employee Severance | 2015 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			(49)		0
Restructuring charges					(191)
Restructuring Reserve, Settled without Cash			0		0
Restructuring Reserve	142		142		191			142
Employee Severance | 2014 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			(53)		(65)	(8)
Restructuring charges						(191)
Restructuring Reserve, Settled without Cash			0		0	0
Restructuring Reserve	65		65		118	183		65
Employee Severance | 2013 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			(39)		(113)	(144)	(26)
Restructuring charges							(392)
Restructuring Reserve, Settled without Cash			0		0	0	0
Restructuring Reserve	46		46		85	198	335	46
Employee Severance | 2013 Restructuring Plan | Transfer From Held for Sale [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Accrual Adjustment						31
Fixed Asset Impairment | 2015 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			0		0
Restructuring charges					(183)
Restructuring Reserve, Settled without Cash			0		183
Restructuring Reserve	0		0		0			0
Fixed Asset Impairment | 2014 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			0		0	0
Restructuring charges						(134)
Restructuring Reserve, Settled without Cash			0		0	134
Restructuring Reserve	0		0		0	0		0
Fixed Asset Impairment | 2013 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			0		0	0	0
Restructuring charges							(156)
Restructuring Reserve, Settled without Cash			0		0	0	156
Restructuring Reserve	0		0		0	0	0	0
Fixed Asset Impairment | 2013 Restructuring Plan | Transfer From Held for Sale [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Accrual Adjustment						0
Other Restructuring | 2015 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			(23)		0
Restructuring charges					(23)
Restructuring Reserve, Settled without Cash			0		0
Restructuring Reserve	0		0		23			0
Other Restructuring | 2014 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			0		(5)	0
Restructuring charges						(5)
Restructuring Reserve, Settled without Cash			0		0	0
Restructuring Reserve	0		0		0	5		0
Other Restructuring | 2013 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			0		0	(3)	0
Restructuring charges							(7)
Restructuring Reserve, Settled without Cash			0		0	0	4
Restructuring Reserve	0		0		0	0	3	0
Other Restructuring | 2013 Restructuring Plan | Transfer From Held for Sale [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Accrual Adjustment						0
Currency Translation | 2015 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			0		0
Restructuring charges					0
Restructuring Reserve, Settled without Cash			0		0
Restructuring Reserve	0		0		0			0
Currency Translation | 2014 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			0		0	0
Restructuring charges						0
Restructuring Reserve, Settled without Cash			2		13	6
Restructuring Reserve	21		21		19	6		21
Currency Translation | 2013 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			0		0	0	0
Restructuring charges							0
Restructuring Reserve, Settled without Cash			1		10	11	4
Restructuring Reserve	$ 18		$ 18		$ 17	7	$ 4	$ 18
Currency Translation | 2013 Restructuring Plan | Transfer From Held for Sale [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Accrual Adjustment						$ 0