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

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Financial Instruments (Net Investment Hedge) (Details) € in Millions, $ in Millions	12 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2019 EUR (€)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) to other comprehensive income, pretax \| $	$ (4)		$ 2	$ 55
Foreign currency [Member] \| Net Investment Hedging [Member] \| Other Comprehensive Income (Loss) [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) to other comprehensive income, pretax \| $	70
Gain (loss) to other comprehensive income, after-tax \| $	$ 54
1.25 Percent Notes Due October 2025 [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Proceeds from issuance of debt \| €		€ 500
Notes interest rate, percentage	1.25%	1.25%
2.0 Percent Notes Due October 2029 [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Proceeds from issuance of debt \| €		€ 500
Notes interest rate, percentage	2.00%	2.00%
0.375 Percent Notes Due May 2024 [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Proceeds from issuance of debt \| €		€ 500
Notes interest rate, percentage	0.375%	0.375%