Plan Assets by Asset Category (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
U.S. Pension Plans
Retirement Plans [Line Items]
Fair value of plan assets	$ 2,504	$ 2,656	$ 2,985
U.S. Pension Plans | Cash
Retirement Plans [Line Items]
Fair value of plan assets	25	30
U.S. Pension Plans | Large-Cap
Retirement Plans [Line Items]
Fair value of plan assets	435	525
U.S. Pension Plans | Small-Cap
Retirement Plans [Line Items]
Fair value of plan assets	224	261
U.S. Pension Plans | International-Developed
Retirement Plans [Line Items]
Fair value of plan assets	443	523
U.S. Pension Plans | Government
Retirement Plans [Line Items]
Fair value of plan assets	220	173
U.S. Pension Plans | Corporate/Other
Retirement Plans [Line Items]
Fair value of plan assets	822	842
U.S. Pension Plans | Hedge Funds
Retirement Plans [Line Items]
Fair value of plan assets	4	17
U.S. Pension Plans | Real Estate
Retirement Plans [Line Items]
Fair value of plan assets	331	285
Non-U.S. Pension
Retirement Plans [Line Items]
Fair value of plan assets	1,201	1,656	1,657
Non-U.S. Pension | Cash
Retirement Plans [Line Items]
Fair value of plan assets	178	30
Non-U.S. Pension | Large-Cap
Retirement Plans [Line Items]
Fair value of plan assets	68	132
Non-U.S. Pension | International-Developed
Retirement Plans [Line Items]
Fair value of plan assets	112	371
Non-U.S. Pension | International - Emerging
Retirement Plans [Line Items]
Fair value of plan assets	16	31
Non-U.S. Pension | Government
Retirement Plans [Line Items]
Fair value of plan assets	300	376
Non-U.S. Pension | Corporate/Other
Retirement Plans [Line Items]
Fair value of plan assets	346	531
Non-U.S. Pension | Commodities
Retirement Plans [Line Items]
Fair value of plan assets		6
Non-U.S. Pension | Hedge Funds
Retirement Plans [Line Items]
Fair value of plan assets	155	89
Non-U.S. Pension | Real Estate
Retirement Plans [Line Items]
Fair value of plan assets	26	90
Postretirement Benefits
Retirement Plans [Line Items]
Fair value of plan assets	219	226	223
Postretirement Benefits | Cash
Retirement Plans [Line Items]
Fair value of plan assets	7	10
Postretirement Benefits | Large-Cap
Retirement Plans [Line Items]
Fair value of plan assets	36	36
Postretirement Benefits | Small-Cap
Retirement Plans [Line Items]
Fair value of plan assets	10	12
Postretirement Benefits | International-Developed
Retirement Plans [Line Items]
Fair value of plan assets	24	29
Postretirement Benefits | International - Emerging
Retirement Plans [Line Items]
Fair value of plan assets	14	14
Postretirement Benefits | Government
Retirement Plans [Line Items]
Fair value of plan assets	25	24
Postretirement Benefits | Corporate/Other
Retirement Plans [Line Items]
Fair value of plan assets	73	71
Postretirement Benefits | Commodities
Retirement Plans [Line Items]
Fair value of plan assets	16	17
Postretirement Benefits | Real Estate
Retirement Plans [Line Items]
Fair value of plan assets	14	13
Quoted Prices in Active Markets (Level 1) | U.S. Pension Plans
Retirement Plans [Line Items]
Fair value of plan assets	1,996	2,157
Quoted Prices in Active Markets (Level 1) | U.S. Pension Plans | Cash
Retirement Plans [Line Items]
Fair value of plan assets	25	30
Quoted Prices in Active Markets (Level 1) | U.S. Pension Plans | Large-Cap
Retirement Plans [Line Items]
Fair value of plan assets	435	525
Quoted Prices in Active Markets (Level 1) | U.S. Pension Plans | Small-Cap
Retirement Plans [Line Items]
Fair value of plan assets	224	261
Quoted Prices in Active Markets (Level 1) | U.S. Pension Plans | International-Developed
Retirement Plans [Line Items]
Fair value of plan assets	443	523
Quoted Prices in Active Markets (Level 1) | U.S. Pension Plans | Government
Retirement Plans [Line Items]
Fair value of plan assets	194	166
Quoted Prices in Active Markets (Level 1) | U.S. Pension Plans | Corporate/Other
Retirement Plans [Line Items]
Fair value of plan assets	675	652
Quoted Prices in Active Markets (Level 1) | U.S. Pension Plans | Hedge Funds
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Quoted Prices in Active Markets (Level 1) | U.S. Pension Plans | Real Estate
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Quoted Prices in Active Markets (Level 1) | Non-U.S. Pension
Retirement Plans [Line Items]
Fair value of plan assets	1,026	1,456
Quoted Prices in Active Markets (Level 1) | Non-U.S. Pension | Cash
Retirement Plans [Line Items]
Fair value of plan assets	178	30
Quoted Prices in Active Markets (Level 1) | Non-U.S. Pension | Large-Cap
Retirement Plans [Line Items]
Fair value of plan assets	68	132
Quoted Prices in Active Markets (Level 1) | Non-U.S. Pension | International-Developed
Retirement Plans [Line Items]
Fair value of plan assets	112	269
Quoted Prices in Active Markets (Level 1) | Non-U.S. Pension | International - Emerging
Retirement Plans [Line Items]
Fair value of plan assets	16	31
Quoted Prices in Active Markets (Level 1) | Non-U.S. Pension | Government
Retirement Plans [Line Items]
Fair value of plan assets	300	376
Quoted Prices in Active Markets (Level 1) | Non-U.S. Pension | Corporate/Other
Retirement Plans [Line Items]
Fair value of plan assets	346	531
Quoted Prices in Active Markets (Level 1) | Non-U.S. Pension | Commodities
Retirement Plans [Line Items]
Fair value of plan assets		6
Quoted Prices in Active Markets (Level 1) | Non-U.S. Pension | Hedge Funds
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Quoted Prices in Active Markets (Level 1) | Non-U.S. Pension | Real Estate
Retirement Plans [Line Items]
Fair value of plan assets	6	81
Quoted Prices in Active Markets (Level 1) | Postretirement Benefits
Retirement Plans [Line Items]
Fair value of plan assets	219	226
Quoted Prices in Active Markets (Level 1) | Postretirement Benefits | Cash
Retirement Plans [Line Items]
Fair value of plan assets	7	10
Quoted Prices in Active Markets (Level 1) | Postretirement Benefits | Large-Cap
Retirement Plans [Line Items]
Fair value of plan assets	36	36
Quoted Prices in Active Markets (Level 1) | Postretirement Benefits | Small-Cap
Retirement Plans [Line Items]
Fair value of plan assets	10	12
Quoted Prices in Active Markets (Level 1) | Postretirement Benefits | International-Developed
Retirement Plans [Line Items]
Fair value of plan assets	24	29
Quoted Prices in Active Markets (Level 1) | Postretirement Benefits | International - Emerging
Retirement Plans [Line Items]
Fair value of plan assets	14	14
Quoted Prices in Active Markets (Level 1) | Postretirement Benefits | Government
Retirement Plans [Line Items]
Fair value of plan assets	25	24
Quoted Prices in Active Markets (Level 1) | Postretirement Benefits | Corporate/Other
Retirement Plans [Line Items]
Fair value of plan assets	73	71
Quoted Prices in Active Markets (Level 1) | Postretirement Benefits | Commodities
Retirement Plans [Line Items]
Fair value of plan assets	16	17
Quoted Prices in Active Markets (Level 1) | Postretirement Benefits | Real Estate
Retirement Plans [Line Items]
Fair value of plan assets	14	13
Significant Other Observable Inputs (Level 2) | U.S. Pension Plans
Retirement Plans [Line Items]
Fair value of plan assets	173	197
Significant Other Observable Inputs (Level 2) | U.S. Pension Plans | Cash
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Significant Other Observable Inputs (Level 2) | U.S. Pension Plans | Large-Cap
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Significant Other Observable Inputs (Level 2) | U.S. Pension Plans | Small-Cap
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Significant Other Observable Inputs (Level 2) | U.S. Pension Plans | International-Developed
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Significant Other Observable Inputs (Level 2) | U.S. Pension Plans | Government
Retirement Plans [Line Items]
Fair value of plan assets	26	7
Significant Other Observable Inputs (Level 2) | U.S. Pension Plans | Corporate/Other
Retirement Plans [Line Items]
Fair value of plan assets	147	190
Significant Other Observable Inputs (Level 2) | U.S. Pension Plans | Hedge Funds
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Significant Other Observable Inputs (Level 2) | U.S. Pension Plans | Real Estate
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Significant Other Observable Inputs (Level 2) | Non-U.S. Pension
Retirement Plans [Line Items]
Fair value of plan assets	155	102
Significant Other Observable Inputs (Level 2) | Non-U.S. Pension | Cash
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Significant Other Observable Inputs (Level 2) | Non-U.S. Pension | Large-Cap
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Significant Other Observable Inputs (Level 2) | Non-U.S. Pension | International-Developed
Retirement Plans [Line Items]
Fair value of plan assets	0	102
Significant Other Observable Inputs (Level 2) | Non-U.S. Pension | International - Emerging
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Significant Other Observable Inputs (Level 2) | Non-U.S. Pension | Government
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Significant Other Observable Inputs (Level 2) | Non-U.S. Pension | Corporate/Other
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Significant Other Observable Inputs (Level 2) | Non-U.S. Pension | Commodities
Retirement Plans [Line Items]
Fair value of plan assets		0
Significant Other Observable Inputs (Level 2) | Non-U.S. Pension | Hedge Funds
Retirement Plans [Line Items]
Fair value of plan assets	155	0
Significant Other Observable Inputs (Level 2) | Non-U.S. Pension | Real Estate
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Significant Other Observable Inputs (Level 2) | Postretirement Benefits
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Significant Other Observable Inputs (Level 2) | Postretirement Benefits | Cash
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Significant Other Observable Inputs (Level 2) | Postretirement Benefits | Large-Cap
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Significant Other Observable Inputs (Level 2) | Postretirement Benefits | Small-Cap
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Significant Other Observable Inputs (Level 2) | Postretirement Benefits | International-Developed
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Significant Other Observable Inputs (Level 2) | Postretirement Benefits | International - Emerging
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Significant Other Observable Inputs (Level 2) | Postretirement Benefits | Government
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Significant Other Observable Inputs (Level 2) | Postretirement Benefits | Corporate/Other
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Significant Other Observable Inputs (Level 2) | Postretirement Benefits | Commodities
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Significant Other Observable Inputs (Level 2) | Postretirement Benefits | Real Estate
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 | U.S. Pension Plans
Retirement Plans [Line Items]
Fair value of plan assets	335	302	334
Fair Value, Inputs, Level 3 | U.S. Pension Plans | Cash
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 | U.S. Pension Plans | Large-Cap
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 | U.S. Pension Plans | Small-Cap
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 | U.S. Pension Plans | International-Developed
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 | U.S. Pension Plans | Government
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 | U.S. Pension Plans | Corporate/Other
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 | U.S. Pension Plans | Hedge Funds
Retirement Plans [Line Items]
Fair value of plan assets	4	17	94
Fair Value, Inputs, Level 3 | U.S. Pension Plans | Real Estate
Retirement Plans [Line Items]
Fair value of plan assets	331	285	240
Fair Value, Inputs, Level 3 | Non-U.S. Pension
Retirement Plans [Line Items]
Fair value of plan assets	20	98	64
Fair Value, Inputs, Level 3 | Non-U.S. Pension | Cash
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 | Non-U.S. Pension | Large-Cap
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 | Non-U.S. Pension | International-Developed
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 | Non-U.S. Pension | International - Emerging
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 | Non-U.S. Pension | Government
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 | Non-U.S. Pension | Corporate/Other
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 | Non-U.S. Pension | Commodities
Retirement Plans [Line Items]
Fair value of plan assets		0
Fair Value, Inputs, Level 3 | Non-U.S. Pension | Hedge Funds
Retirement Plans [Line Items]
Fair value of plan assets	0	89	56
Fair Value, Inputs, Level 3 | Non-U.S. Pension | Real Estate
Retirement Plans [Line Items]
Fair value of plan assets	20	9	8
Fair Value, Inputs, Level 3 | Postretirement Benefits
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 | Postretirement Benefits | Cash
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 | Postretirement Benefits | Large-Cap
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 | Postretirement Benefits | Small-Cap
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 | Postretirement Benefits | International-Developed
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 | Postretirement Benefits | International - Emerging
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 | Postretirement Benefits | Government
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 | Postretirement Benefits | Corporate/Other
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 | Postretirement Benefits | Commodities
Retirement Plans [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 | Postretirement Benefits | Real Estate
Retirement Plans [Line Items]
Fair value of plan assets	$ 0	$ 0