Retirement Plans (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Sep. 30, 2013 Age Person	Sep. 30, 2012 Age	Sep. 30, 2011
Retirement Plans [Line Items]
Defined benefit plan, pension plans with accumulated benefit obligations in excess of plan assets, aggregate projected benefit obligation	$ 3,069	$ 4,450
Defined benefit plan, pension plans with accumulated benefit obligations in excess of plan assets, aggregate accumulated benefit obligation	2,981	4,242
Defined benefit plan, pension plans with accumulated benefit obligations in excess of plan assets, aggregate fair value of plan assets	2,392	3,279
Total employer and employee contributions to defined benefit plans	95
Voluntary contributions made by the company to defined benefit plans	1
Estimated future employer contributions to defined benefit plans in next fiscal year	80
Modification in salaried plans to limit company's cost of future annual retiree medical benefits	150.00%
Threshold age for retirement calculations	65	65
Projected prescription drug subsidy receipts per year over the next ten years	3
Matching contributions charged to expense for defined contribution savings plans	118	105	105
Number of multiemployer benefit plans in which the Company participates	300
Employer contributions to multiemployer pension plans	44	47	51
Projected Benefit Obligation Held For Sale	14
U.S. Postretirement Benefits - Medical
Retirement Plans [Line Items]
Accumulated postretirement benefit obligation for both pre-65 and post-65, assumed health care cost trend rates	7.50%	7.50%
Accumulated postretirement benefit obligation for both pre-65 and post-65, assumed health care cost ultimate trend rates	5.00%	5.00%
Defined benefit plan, description of direction and pattern of change for assumed health care cost trend rate	Decreasing one half percent to one quarter percent each year to an ultimate rate	Decreasing one half percent each year to an ultimate rate
Non-U.S. Postretirement Benefits - Medical
Retirement Plans [Line Items]
Accumulated postretirement benefit obligation for both pre-65 and post-65, assumed health care cost trend rates	7.25%	7.50%
Accumulated postretirement benefit obligation for both pre-65 and post-65, assumed health care cost ultimate trend rates	4.50%	4.50%
Defined benefit plan, description of direction and pattern of change for assumed health care cost trend rate	Decreasing three twentieths of one percent each year to an ultimate rate	Decreasing three twentieths of one percent each year to an ultimate rate
U.S. Postretirement Benefits - Prescription Drug
Retirement Plans [Line Items]
Accumulated postretirement benefit obligation for both pre-65 and post-65, assumed health care cost trend rates	7.50%	7.50%
Accumulated postretirement benefit obligation for both pre-65 and post-65, assumed health care cost ultimate trend rates	5.00%	5.00%
Defined benefit plan, description of direction and pattern of change for assumed health care cost trend rate	Decreasing one half percent to one quarter percent each year to an ultimate rate	Decreasing one half percent each year to an ultimate rate
Non-U.S. Postretirement Benefits - Prescription Drug
Retirement Plans [Line Items]
Accumulated postretirement benefit obligation for both pre-65 and post-65, assumed health care cost trend rates	8.15%	8.50%
Accumulated postretirement benefit obligation for both pre-65 and post-65, assumed health care cost ultimate trend rates	4.50%	4.50%
Defined benefit plan, description of direction and pattern of change for assumed health care cost trend rate	Decreasing one fifth of one percent each year to an ultimate rate	Decreasing one fifth of one percent each year to an ultimate rate
Postretirement Benefits
Retirement Plans [Line Items]
Total employer and employee contributions to defined benefit plans	13
Voluntary contributions made by the company to defined benefit plans	$ 12