Note 9. Derivative Instruments and Hedging Activities Derivative Assets and Liabilities (Details) $ in Millions, € in Billions	Sep. 30, 2017 USD ($)	Sep. 30, 2017 EUR (€)	Jun. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	$ 5			$ 9
Derivative Liability	1,189			1,150
Designated as Hedging Instrument [Member] | Long-term Debt [Member]
Derivatives, Fair Value [Line Items]
Derivative Instruments in Hedges, Net Investment in Foreign Operations, Liabilities, Fair Value	1,180	€ 1.0		1,119
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	3			40
Derivative Liability	2			8
Not Designated as Hedging Instrument [Member] | Long-term Debt [Member]
Derivatives, Fair Value [Line Items]
Derivative Instruments in Hedges, Net Investment in Foreign Operations, Liabilities, Fair Value	0			0
Foreign Exchange Contract [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Current	4			49
Derivative Liability, Current	1
Foreign Exchange Contract [Member] | Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Current	8			39
Foreign Exchange Contract [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Current	3
Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Current			$ 4	9
Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member] | Other Noncurrent Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Current	1			0
Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member] | Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Current			6	31
Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Current	3			0
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Current			0	40
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member] | Other Noncurrent Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Current	0			0
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member] | Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Current			$ 2	8
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member] | Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Current	0			0
Equity Swap [Member] | Other Noncurrent Assets [Member]
Derivatives, Fair Value [Line Items]
Hedging Assets, Noncurrent	3
Equity Swap [Member] | Designated as Hedging Instrument [Member] | Other Noncurrent Assets [Member]
Derivatives, Fair Value [Line Items]
Hedging Assets, Noncurrent	0			0
Equity Swap [Member] | Not Designated as Hedging Instrument [Member] | Other Noncurrent Assets [Member]
Derivatives, Fair Value [Line Items]
Hedging Assets, Noncurrent	$ 3			$ 0
Unsecured Debt [Member] | Euro Member Countries, Euro
Derivatives, Fair Value [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.50%	3.50%