Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

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Amount of unrealized gain before deducting unrealized loss on investments in debt and equity securities classified as available-for-sale securities.

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Amount of unrealized loss before deducting unrealized gain on investments in available-for-sale securities.

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Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Amount of the hedged item as of the balance sheet date related to the derivative. For example, the hedged balance on a debt instrument.

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This item represents the total realized gain (loss) included in earnings for the period as a result of selling marketable securities categorized as trading, available-for-sale, or held-to-maturity. Additionally, this item would include any losses recognized for other than temporary impairments (OTTI) of the subject investments in debt and equity securities.

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Number of interest rate derivative instruments held by the entity at the reporting date.

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The cash inflow associated with the aggregate amount received by the entity through sale or maturity of marketable securities (held-to-maturity or available-for-sale) during the period.

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Fair Value Measurements Fair Value Disclosure, Additional Information (Details) € in Millions, $ in Millions, ¥ in Billions	12 Months Ended
	Sep. 30, 2018 USD ($) Swap	Sep. 30, 2017 USD ($)	Sep. 30, 2018 EUR (€) Swap	Sep. 30, 2018 JPY (¥) Swap	Sep. 30, 2017 EUR (€)	Sep. 30, 2017 JPY (¥)	Sep. 30, 2016 USD ($) Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Gross Unrealized Gain	$ 23	$ 10
Net Realized and Unrealized Gain (Loss) on Trading Securities	$ 15	6
Number of fixed to floating interest rate swaps outstanding \| Swap	0		0	0
Debt Instrument, Fair Value Disclosure	$ 9,600	12,700
Proceeds from Sale and Maturity of Marketable Securities	3
Marketable Securities, Realized Gain (Loss)	$ 2
1.4% Due in 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	1.40%		1.40%	1.40%
Foreign Currency Denominated Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Notional Amount \| ¥				¥ 35		¥ 35
Interest rate swaps \| Two Point Six Percent Due Two Thousand Seventeen
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Amount of Hedged Item							$ 400
Debt Instrument, Interest Rate, Stated Percentage							2.60%
Number of fixed to floating interest rate swaps outstanding \| Swap							4
Interest rate swaps \| 1.4% Due in 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Amount of Hedged Item							$ 300
Debt Instrument, Interest Rate, Stated Percentage							1.40%
Number of fixed to floating interest rate swaps outstanding \| Swap							3
Interest rate swaps \| 7.125 % Due in 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Amount of Hedged Item							$ 150
Debt Instrument, Interest Rate, Stated Percentage							7.125%
Number of fixed to floating interest rate swaps outstanding \| Swap							1
One billion euro net investment hedge [Member] \| Foreign Currency Denominated Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Notional Amount \| €			€ 1,000		€ 1,000
500 million euro net investment hedge [Member] [Member] \| Foreign Currency Denominated Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Notional Amount \| €					€ 423
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	$ 1,000	$ 4,100
Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Fair Value Disclosure	$ 8,600