Significant Restructuring Costs - Additional Information (Detail) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended			42 Months Ended
	Mar. 31, 2016 USD ($) Employees Plant	Mar. 31, 2015 USD ($)	Mar. 31, 2016 USD ($) Employees Plant	Mar. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2013 USD ($)	Mar. 31, 2016 USD ($) Employees Plant
Restructuring Cost and Reserve [Line Items]
Original Reserve	$ (229)	$ 0	$ (229)	$ 0
Number of employees to be severed | Employees								17,100
Number of employees severed | Employees	10,400		10,400					10,400
Number of plants to be closed | Plant								26
Plants closed | Plant	10		10					10
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								10,000
Number of plants to be closed | Plant								18
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								8
2015 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			$ (60)		$ 0
Original Reserve					(397)
Restructuring Reserve, Settled without Cash			2		183
Restructuring Reserve	$ 156		156		214			$ 156
2015 Restructuring Plan [Domain] | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve					(397)
2014 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			(31)		(70)	$ (8)
Original Reserve						(377)
Restructuring Reserve, Settled without Cash			2		13	187
Restructuring Reserve	66		66		99	182		66
2014 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve						(324)
2014 Restructuring Plan | Automotive Experience Electronics | Discontinued Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve						(53)
2013 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			(33)		(113)	(147)	$ (26)
Original Reserve							(985)
Restructuring Reserve, Settled without Cash			1		10	11	586
Restructuring Reserve	34		34		68	191	342	34
2013 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve							(903)
2013 Restructuring Plan | Discontinued Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve							(82)
2013 Restructuring Plan | Global Workplace Solutions | Discontinued Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve							(54)
2013 Restructuring Plan | Automotive Experience Electronics | Discontinued Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve							(28)
Building Efficiency Systems and Service North America | 2015 Restructuring Plan [Domain] | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve					(3)
Building Efficiency Systems and Service North America | 2014 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve						(12)
Building Efficiency Systems and Service North America | 2013 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve							(35)
Building Efficiency Products North America | 2015 Restructuring Plan [Domain] | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve					(11)
Building Efficiency Products North America | 2014 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve						(7)
Building Efficiency Products North America | 2013 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve							(28)
Automotive Experience Interiors | 2014 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve						(130)
Automotive Experience Interiors | 2013 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve							(560)
Automotive Experience Seating [Member] | 2015 Restructuring Plan [Domain] | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve					(182)
Automotive Experience Seating [Member] | 2014 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve						(29)
Automotive Experience Seating [Member] | 2013 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve							(152)
Building Efficiency Rest of World [Member] | 2015 Restructuring Plan [Domain] | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve					(13)
Building Efficiency Rest of World [Member] | 2014 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve						(119)
Building Efficiency Rest of World [Member] | 2013 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve							(70)
Power Solutions | 2015 Restructuring Plan [Domain] | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve					(11)
Power Solutions | 2014 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve						(16)
Power Solutions | 2013 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve							(36)
Corporate Segment | 2015 Restructuring Plan [Domain] | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve					(166)
Corporate Segment | 2014 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve						(7)
Corporate Segment | 2013 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve							(17)
Building Efficiency Asia | 2015 Restructuring Plan [Domain] | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve					(11)
Building Efficiency Asia | 2014 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve						(4)
Building Efficiency Asia | 2013 Restructuring Plan | Continuing Operations
Restructuring Cost and Reserve [Line Items]
Original Reserve							(5)
Employee Severance | 2015 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			(37)		0
Original Reserve					(191)
Restructuring Reserve, Settled without Cash			0		0
Restructuring Reserve	154		154		191			154
Employee Severance | 2014 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			(31)		(65)	(8)
Original Reserve						(191)
Restructuring Reserve, Settled without Cash			0		0	0
Restructuring Reserve	87		87		118	183		87
Employee Severance | 2013 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			(33)		(113)	(144)	(26)
Original Reserve							(392)
Restructuring Reserve, Settled without Cash			0		0	0	0
Restructuring Reserve	52		52		85	198	335	52
Fixed Asset Impairment | 2015 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			0		0
Original Reserve					(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
Original Reserve						(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
Original Reserve							(156)
Restructuring Reserve, Settled without Cash			0		0	0	156
Restructuring Reserve	0		0		0	0	0	0
Other Restructuring | 2015 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			(23)		0
Original Reserve					(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
Original Reserve						(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
Original Reserve							(7)
Restructuring Reserve, Settled without Cash			0		0	0	4
Restructuring Reserve	0		0		0	0	3	0
Currency Translation | 2015 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			0		0
Original Reserve					0
Restructuring Reserve, Settled without Cash			2		0
Restructuring Reserve	2		2		0			2
Currency Translation | 2014 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			0		0	0
Original Reserve						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
Original Reserve							0
Restructuring Reserve, Settled without Cash			1		10	11	4
Restructuring Reserve	$ 18		$ 18		$ 17	$ 7	$ 4	$ 18