Retirement Plans (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Defined Benefit Plan Disclosure [Line Items]
Gains (Losses) deferred in accumulated other comprehensive income will be amortized into earnings in 2019		$ (85)
Losses deferred in accumulated other comprehensive income		(712)
Total accumulated benefit obligation		5,154	$ 5,607
Accumulated benefit obligations in excess of plan assets for retirement plans, projected benefit obligation		585	1,182
Accumulated benefit obligations in excess of plan assets for retirement plans, accumulated benefit obligation		508	1,088
Accumulated benefit obligations in excess of plan assets for retirement plans, fair value of plan assets		87	663
Pension contribution		61	45	$ 66
Pension expense		49	127	$ 95
Scenario, Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension contribution	$ 60
U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Funded status of plan		276	$ (77)
Over (Under) funded plans		276
Unfunded plans		182
Future benefit payments, 2019		214
Future benefit payments, 2020		221
Future benefit payments, 2021		228
Future benefit payments, 2022		234
Future benefit payments, 2023		239
Total future benefit payments, 2024 - 2028		$ 1,252
Discount rate		4.26%	3.76%	3.50%
Pension expense		$ 39	$ 115	$ 77
Defined contribution plans		132	96	104
U.S. Plans | Discontinued Operations, Held-for-sale [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension expense			3	12
Defined contribution plans			6	$ 34
Non-U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Funded status of plan		(199)	$ (253)
Over (Under) funded plans		(199)
Unfunded plans		270
Future benefit payments, 2019		83
Future benefit payments, 2020		83
Future benefit payments, 2021		88
Future benefit payments, 2022		95
Future benefit payments, 2023		99
Total future benefit payments, 2024 - 2028		$ 569
Discount rate		2.70%	2.60%	2.30%
Pension expense		$ 10	$ 15	$ 30
Defined contribution plans		$ 52	$ 47	$ 56