Amount of total entity’s unfunded plans.

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Period distributions of underlying assets are expected to occur

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Amount of actuarial present value of benefits attributed to employee service rendered, excluding assumptions about future compensation level.

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Amount, before tax, of accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.

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Amount of asset (liability), recognized in statement of financial position, for defined benefit pension and other postretirement plans.

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Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan.

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Amount of payment to participant of defined benefit plan which decreases benefit obligation. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of cost (credit) included in accumulated other comprehensive (income) loss expected to be recognized in net periodic benefit cost (credit) for fiscal year following most recent annual statement of financial position.

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Amount of benefits for defined benefit plan expected to be paid in five fiscal years after fifth fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in next fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in fifth fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in fourth fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in third fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in second fiscal year following latest fiscal year.

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Amount of funded (unfunded) status of defined benefit plan, measured as difference between fair value of plan assets and benefit obligation. Includes, but is not limited to, overfunded (underfunded) status.

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Amount of net periodic benefit cost (credit) for defined benefit plan.

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Amount of accumulated benefit obligation for defined benefit plan with accumulated benefit obligation in excess of plan assets.

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Amount of plan asset for defined benefit plan with accumulated benefit obligation in excess of plan assets.

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Amount of projected benefit obligation for defined benefit pension plan with accumulated benefit obligation in excess of plan assets.

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The amount of unfunded commitments for which the entity is obligated, to those certain investments for which net asset value per share is calculated (including by unit, membership interest, or other equity (ownership interest) unit measure) (alternative investments).

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Amount of cash outflow for pension benefit. Includes, but is not limited to, employer contribution to fund plan asset and payment to retiree. Excludes other postretirement benefit.

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Retirement Plans (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Defined Benefit Plan Disclosure [Line Items]
Gains (Losses) deferred in accumulated other comprehensive income will be amortized into earnings in 2021		$ (159)
Gains (Losses) deferred in accumulated other comprehensive income		(1,253)
Total accumulated benefit obligation		5,859	$ 5,682
Accumulated benefit obligations in excess of plan assets for retirement plans, projected benefit obligation		1,153	1,113
Accumulated benefit obligations in excess of plan assets for retirement plans, accumulated benefit obligation		1,034	991
Accumulated benefit obligations in excess of plan assets for retirement plans, fair value of plan assets		492	456
Pension contribution		66	60	$ 61
Post retirement plans expense		67	2	49
Postretirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Gains (Losses) deferred in accumulated other comprehensive income		106	118
Future benefit payments, 2021		12
Future benefit payments, 2022		12
Future benefit payments, 2023		12
Future benefit payments, 2024		12
Future benefit payments, 2025		12
Total future benefit payments, 2026 - 2030		42
Benefit obligation, ending (recognized in balance sheet)		135	147
Post retirement plans expense		(12)	(12)	$ (12)
Benefits paid		(12)	$ (13)
Fair Value Measured at Net Asset Value Per Share [Member] \| Private Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Unfunded commitments for private equity funds		$ 240
Period distributions of underlying assets are expected to occur		10 years
Scenario, Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension contribution	$ 50
U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Over (Under) funded plans		$ (142)
Unfunded plans		(223)
Future benefit payments, 2021		212
Future benefit payments, 2022		219
Future benefit payments, 2023		225
Future benefit payments, 2024		231
Future benefit payments, 2025		235
Total future benefit payments, 2026 - 2030		$ 1,219
Discount rate		2.81%	3.22%	4.26%
Benefit obligation, ending (recognized in balance sheet)		$ (142)	$ (202)
Post retirement plans expense		62	2	$ 39
Benefits paid		(202)	$ (206)
Non-U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Over (Under) funded plans		(266)
Unfunded plans		(319)
Future benefit payments, 2021		72
Future benefit payments, 2022		72
Future benefit payments, 2023		72
Future benefit payments, 2024		78
Future benefit payments, 2025		79
Total future benefit payments, 2026 - 2030		$ 441
Discount rate		1.90%	1.90%	2.70%
Benefit obligation, ending (recognized in balance sheet)		$ (266)	$ (300)
Post retirement plans expense		5	0	$ 10
Benefits paid		$ (37)	$ (36)