Significant Restructuring Costs Change in Restructuring Reserve - 2016 Restructuring Plan (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015	Sep. 30, 2015
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 229	$ 0	$ 229	$ 0
2016 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	229
Payments for Restructuring			(4)
Restructuring Reserve, Settled without Cash			(27)
Restructuring Reserve	198		198
2015 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges					$ 397
Payments for Restructuring			(60)		0
Restructuring Reserve, Settled without Cash			(2)		(183)
Restructuring Reserve	156		156		214
Employee Severance | 2016 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	194
Payments for Restructuring			(3)
Restructuring Reserve, Settled without Cash			0
Restructuring Reserve	191		191
Employee Severance | 2015 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges					191
Payments for Restructuring			(37)		0
Restructuring Reserve, Settled without Cash			0		0
Restructuring Reserve	154		154		191
Fixed Asset Impairment | 2016 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	29
Payments for Restructuring			0
Restructuring Reserve, Settled without Cash			(29)
Restructuring Reserve	0		0
Fixed Asset Impairment | 2015 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges					183
Payments for Restructuring			0		0
Restructuring Reserve, Settled without Cash			0		(183)
Restructuring Reserve	0		0		0
Other Restructuring | 2016 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	6
Payments for Restructuring			(1)
Restructuring Reserve, Settled without Cash			0
Restructuring Reserve	5		5
Other Restructuring | 2015 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges					23
Payments for Restructuring			(23)		0
Restructuring Reserve, Settled without Cash			0		0
Restructuring Reserve	0		0		23
Currency Translation | 2016 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	0
Payments for Restructuring			0
Restructuring Reserve, Settled without Cash			(2)
Restructuring Reserve	2		2
Currency Translation | 2015 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges					0
Payments for Restructuring			0		0
Restructuring Reserve, Settled without Cash			(2)		0
Restructuring Reserve	$ 2		2		0
Continuing Operations | 2016 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			229
Continuing Operations | 2015 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges					397
Continuing Operations | Building Efficiency Systems and Service North America | 2016 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			2
Continuing Operations | Building Efficiency Systems and Service North America | 2015 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges					3
Continuing Operations | Automotive Experience Seating [Member] | 2016 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			169
Continuing Operations | Automotive Experience Seating [Member] | 2015 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges					182
Continuing Operations | Building Efficiency Asia | 2016 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			26
Continuing Operations | Building Efficiency Asia | 2015 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges					11
Continuing Operations | Building Efficiency Rest of World [Member] | 2016 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			16
Continuing Operations | Building Efficiency Rest of World [Member] | 2015 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges					13
Continuing Operations | Building Efficiency Products North America | 2016 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			9
Continuing Operations | Building Efficiency Products North America | 2015 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges					11
Continuing Operations | Corporate Segment | 2016 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			$ 7
Continuing Operations | Corporate Segment | 2015 Restructuring Plan [Domain]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges					$ 166