Plan Assets by Asset Category (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
U.S. Pension Plans
Retirement Plans [Line Items]
Fair value of plan assets	$ 2,656	$ 2,985	$ 2,372
U.S. Pension Plans | Cash
Retirement Plans [Line Items]
Fair value of plan assets	30	25
U.S. Pension Plans | Large-Cap
Retirement Plans [Line Items]
Fair value of plan assets	525	781
U.S. Pension Plans | Small-Cap
Retirement Plans [Line Items]
Fair value of plan assets	261	324
U.S. Pension Plans | International-Developed
Retirement Plans [Line Items]
Fair value of plan assets	523	617
U.S. Pension Plans | Government
Retirement Plans [Line Items]
Fair value of plan assets	173	685
U.S. Pension Plans | Corporate/Other
Retirement Plans [Line Items]
Fair value of plan assets	842	219
U.S. Pension Plans | Hedge Funds
Retirement Plans [Line Items]
Fair value of plan assets	17	94
U.S. Pension Plans | Real Estate
Retirement Plans [Line Items]
Fair value of plan assets	285	240
Non-U.S. Pension
Retirement Plans [Line Items]
Fair value of plan assets	1,656	1,657	1,471
Non-U.S. Pension | Cash
Retirement Plans [Line Items]
Fair value of plan assets	30	61
Non-U.S. Pension | Large-Cap
Retirement Plans [Line Items]
Fair value of plan assets	132	134
Non-U.S. Pension | International-Developed
Retirement Plans [Line Items]
Fair value of plan assets	371	383
Non-U.S. Pension | Government
Retirement Plans [Line Items]
Fair value of plan assets	376	334
Non-U.S. Pension | Corporate/Other
Retirement Plans [Line Items]
Fair value of plan assets	531	540
Non-U.S. Pension | Hedge Funds
Retirement Plans [Line Items]
Fair value of plan assets	89	56
Non-U.S. Pension | Real Estate
Retirement Plans [Line Items]
Fair value of plan assets	90	91
Non-U.S. Pension | International - Emerging
Retirement Plans [Line Items]
Fair value of plan assets	31	46
Non-U.S. Pension | Commodities
Retirement Plans [Line Items]
Fair value of plan assets	6	12
Postretirement Benefits
Retirement Plans [Line Items]
Fair value of plan assets	226	223	156
Postretirement Benefits | Cash
Retirement Plans [Line Items]
Fair value of plan assets	10	6
Postretirement Benefits | Large-Cap
Retirement Plans [Line Items]
Fair value of plan assets	36	35
Postretirement Benefits | Small-Cap
Retirement Plans [Line Items]
Fair value of plan assets	12	11
Postretirement Benefits | International-Developed
Retirement Plans [Line Items]
Fair value of plan assets	29	25
Postretirement Benefits | Government
Retirement Plans [Line Items]
Fair value of plan assets	24	26
Postretirement Benefits | Corporate/Other
Retirement Plans [Line Items]
Fair value of plan assets	71	74
Postretirement Benefits | Real Estate
Retirement Plans [Line Items]
Fair value of plan assets	13	12
Postretirement Benefits | International - Emerging
Retirement Plans [Line Items]
Fair value of plan assets	14	14
Postretirement Benefits | Commodities
Retirement Plans [Line Items]
Fair value of plan assets	17	20
Quoted Prices in Active Markets (Level 1) | U.S. Pension Plans
Retirement Plans [Line Items]
Fair value of plan assets	2,157	2,651
Quoted Prices in Active Markets (Level 1) | U.S. Pension Plans | Cash
Retirement Plans [Line Items]
Fair value of plan assets	30	25
Quoted Prices in Active Markets (Level 1) | U.S. Pension Plans | Large-Cap
Retirement Plans [Line Items]
Fair value of plan assets	525	781
Quoted Prices in Active Markets (Level 1) | U.S. Pension Plans | Small-Cap
Retirement Plans [Line Items]
Fair value of plan assets	261	324
Quoted Prices in Active Markets (Level 1) | U.S. Pension Plans | International-Developed
Retirement Plans [Line Items]
Fair value of plan assets	523	617
Quoted Prices in Active Markets (Level 1) | U.S. Pension Plans | Government
Retirement Plans [Line Items]
Fair value of plan assets	166	685
Quoted Prices in Active Markets (Level 1) | U.S. Pension Plans | Corporate/Other
Retirement Plans [Line Items]
Fair value of plan assets	652	219
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	1,456	1,593
Quoted Prices in Active Markets (Level 1) | Non-U.S. Pension | Cash
Retirement Plans [Line Items]
Fair value of plan assets	30	61
Quoted Prices in Active Markets (Level 1) | Non-U.S. Pension | Large-Cap
Retirement Plans [Line Items]
Fair value of plan assets	132	134
Quoted Prices in Active Markets (Level 1) | Non-U.S. Pension | International-Developed
Retirement Plans [Line Items]
Fair value of plan assets	269	383
Quoted Prices in Active Markets (Level 1) | Non-U.S. Pension | Government
Retirement Plans [Line Items]
Fair value of plan assets	376	334
Quoted Prices in Active Markets (Level 1) | Non-U.S. Pension | Corporate/Other
Retirement Plans [Line Items]
Fair value of plan assets	531	540
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	81	83
Quoted Prices in Active Markets (Level 1) | Non-U.S. Pension | International - Emerging
Retirement Plans [Line Items]
Fair value of plan assets	31	46
Quoted Prices in Active Markets (Level 1) | Non-U.S. Pension | Commodities
Retirement Plans [Line Items]
Fair value of plan assets	6	12
Quoted Prices in Active Markets (Level 1) | Postretirement Benefits
Retirement Plans [Line Items]
Fair value of plan assets	226	223
Quoted Prices in Active Markets (Level 1) | Postretirement Benefits | Cash
Retirement Plans [Line Items]
Fair value of plan assets	10	6
Quoted Prices in Active Markets (Level 1) | Postretirement Benefits | Large-Cap
Retirement Plans [Line Items]
Fair value of plan assets	36	35
Quoted Prices in Active Markets (Level 1) | Postretirement Benefits | Small-Cap
Retirement Plans [Line Items]
Fair value of plan assets	12	11
Quoted Prices in Active Markets (Level 1) | Postretirement Benefits | International-Developed
Retirement Plans [Line Items]
Fair value of plan assets	29	25
Quoted Prices in Active Markets (Level 1) | Postretirement Benefits | Government
Retirement Plans [Line Items]
Fair value of plan assets	24	26
Quoted Prices in Active Markets (Level 1) | Postretirement Benefits | Corporate/Other
Retirement Plans [Line Items]
Fair value of plan assets	71	74
Quoted Prices in Active Markets (Level 1) | Postretirement Benefits | Real Estate
Retirement Plans [Line Items]
Fair value of plan assets	13	12
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 | Commodities
Retirement Plans [Line Items]
Fair value of plan assets	17	20
Significant Other Observable Inputs (Level 2) | U.S. Pension Plans
Retirement Plans [Line Items]
Fair value of plan assets	197	0
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	7	0
Significant Other Observable Inputs (Level 2) | U.S. Pension Plans | Corporate/Other
Retirement Plans [Line Items]
Fair value of plan assets	190	0
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	102	0
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	102	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 | Hedge Funds
Retirement Plans [Line Items]
Fair value of plan assets	0	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) | 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 | Commodities
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 | 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 | Real Estate
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 | Commodities
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	302	334	298
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	17	94	94
Fair Value, Inputs, Level 3 | U.S. Pension Plans | Real Estate
Retirement Plans [Line Items]
Fair value of plan assets	285	240	204
Fair Value, Inputs, Level 3 | Non-U.S. Pension
Retirement Plans [Line Items]
Fair value of plan assets	98	64	7
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 | 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 | Hedge Funds
Retirement Plans [Line Items]
Fair value of plan assets	89	56	0
Fair Value, Inputs, Level 3 | Non-U.S. Pension | Real Estate
Retirement Plans [Line Items]
Fair value of plan assets	9	8	7
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 | Commodities
Retirement Plans [Line Items]
Fair value of plan assets	0	0
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 | 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 | Real Estate
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 | Commodities
Retirement Plans [Line Items]
Fair value of plan assets	$ 0	$ 0