Fair Value Measurements - Schedule of Assets and Liabilities at Fair Value (Details) - USD ($) $ in Millions	Sep. 30, 2021	Sep. 30, 2020
Fair Value, Inputs, Level 1 [Member]
Other noncurrent assets
Total assets at fair value	$ 13	$ 296
Accrued expenses and other liabilities
Total liabilities at fair value	0	0
Level 2
Other noncurrent assets
Total assets at fair value	96	150
Accrued expenses and other liabilities
Total liabilities at fair value	4	3
Assets measured at NAV
Other noncurrent assets
Non-qualified trust funds	7	8
Accrued expenses and other liabilities
Deferred compensation obligations	24	25
Fair Value Measurement, Recurring
Prepaid expenses and other current assets
Foreign Currency Contract, Asset, Fair Value Disclosure	3	3
Other noncurrent assets
Non-qualified trust funds	11	16
Interest rate swap agreements	2
Total assets at fair value	116	454
Accrued expenses and other liabilities
Currency derivatives	3	2
Interest rate swap agreements	1	1
Deferred compensation obligations	24	25
Total liabilities at fair value	28	28
Fair Value Measurement, Recurring | Fair Value, Inputs, Level 1 [Member]
Other noncurrent assets
Non-qualified trust funds	0	0
Fair Value Measurement, Recurring | Level 2
Prepaid expenses and other current assets
Foreign Currency Contract, Asset, Fair Value Disclosure	3	3
Other noncurrent assets
Non-qualified trust funds	4	8
Interest rate swap agreements	2
Accrued expenses and other liabilities
Currency derivatives	3	2
Interest rate swap agreements	1	1
Deferred compensation obligations	0	0
Fair Value Measurement, Recurring | Assets measured at NAV
Other noncurrent assets
Non-qualified trust funds	7	8
Accrued expenses and other liabilities
Deferred compensation obligations	24	25
Money Market Funds [Member] | Fair Value Measurement, Recurring
Cash and cash equivalents
Cash and cash equivalents	13	296
Money Market Funds [Member] | Fair Value Measurement, Recurring | Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents
Cash and cash equivalents	13	296
Time deposits | Fair Value Measurement, Recurring
Cash and cash equivalents
Cash and cash equivalents	87	139
Time deposits | Fair Value Measurement, Recurring | Level 2
Cash and cash equivalents
Cash and cash equivalents	$ 87	$ 139