v3.26.3
Retirement Benefits - Schedule of Allocation of Plan Assets (Details) - USD ($)
$ in Millions
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2024
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets $ 2,488 $ 2,810  
Level 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 68 74 $ 74
U.S. Plans      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 1,505 1,821  
U.S. Plans | Fair Value, Inputs, Level 1, 2 and 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 1,498 1,815  
U.S. Plans | Level 1      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 632 772  
U.S. Plans | Level 2      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 866 1,043  
U.S. Plans | Level 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
U.S. Plans | Cash and cash equivalents | Fair Value, Inputs, Level 1, 2 and 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 44 88  
U.S. Plans | Cash and cash equivalents | Level 1      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 44 88  
U.S. Plans | Cash and cash equivalents | Level 2      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
U.S. Plans | Cash and cash equivalents | Level 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
U.S. Plans | Preferred and common stock | Fair Value, Inputs, Level 1, 2 and 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 303 419  
U.S. Plans | Preferred and common stock | Level 1      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 303 419  
U.S. Plans | Preferred and common stock | Level 2      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
U.S. Plans | Preferred and common stock | Level 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
U.S. Plans | Common collective trusts | Fair Value, Inputs, Level 1, 2 and 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 231 415  
U.S. Plans | Common collective trusts | Level 1      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
U.S. Plans | Common collective trusts | Level 2      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 231 415  
U.S. Plans | Common collective trusts | Level 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
U.S. Plans | Preferred and corporate debt | Fair Value, Inputs, Level 1, 2 and 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 499 478  
U.S. Plans | Preferred and corporate debt | Level 1      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
U.S. Plans | Preferred and corporate debt | Level 2      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 499 478  
U.S. Plans | Preferred and corporate debt | Level 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
U.S. Plans | Government securities | Fair Value, Inputs, Level 1, 2 and 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 304 295  
U.S. Plans | Government securities | Level 1      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 285 265  
U.S. Plans | Government securities | Level 2      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 19 30  
U.S. Plans | Government securities | Level 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
U.S. Plans | Common collective trusts | Fair Value, Inputs, Level 1, 2 and 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 117 120  
U.S. Plans | Common collective trusts | Level 1      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
U.S. Plans | Common collective trusts | Level 2      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 117 120  
U.S. Plans | Common collective trusts | Level 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
U.S. Plans | Private equity and alternative equity | Fair Value Measured at Net Asset Value Per Share      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 7 6  
Non-U.S. Plans      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 983 989  
Non-U.S. Plans | Fair Value, Inputs, Level 1, 2 and 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 960 967  
Non-U.S. Plans | Level 1      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 173 209  
Non-U.S. Plans | Level 2      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 719 684  
Non-U.S. Plans | Level 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 68 74  
Non-U.S. Plans | Cash and cash equivalents | Fair Value, Inputs, Level 1, 2 and 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 10 8  
Non-U.S. Plans | Cash and cash equivalents | Level 1      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 10 8  
Non-U.S. Plans | Cash and cash equivalents | Level 2      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
Non-U.S. Plans | Cash and cash equivalents | Level 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
Non-U.S. Plans | Preferred and common stock | Fair Value, Inputs, Level 1, 2 and 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 163 200  
Non-U.S. Plans | Preferred and common stock | Level 1      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 163 200  
Non-U.S. Plans | Preferred and common stock | Level 2      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
Non-U.S. Plans | Preferred and common stock | Level 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
Non-U.S. Plans | Common collective trusts | Fair Value, Inputs, Level 1, 2 and 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 204 218  
Non-U.S. Plans | Common collective trusts | Level 1      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
Non-U.S. Plans | Common collective trusts | Level 2      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 204 218  
Non-U.S. Plans | Common collective trusts | Level 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
Non-U.S. Plans | Preferred and corporate debt | Fair Value, Inputs, Level 1, 2 and 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 68 79  
Non-U.S. Plans | Preferred and corporate debt | Level 1      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
Non-U.S. Plans | Preferred and corporate debt | Level 2      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 68 79  
Non-U.S. Plans | Preferred and corporate debt | Level 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
Non-U.S. Plans | Government securities | Fair Value, Inputs, Level 1, 2 and 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 1  
Non-U.S. Plans | Government securities | Level 1      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 1  
Non-U.S. Plans | Government securities | Level 2      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
Non-U.S. Plans | Government securities | Level 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
Non-U.S. Plans | Common collective trusts | Fair Value, Inputs, Level 1, 2 and 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 386 327  
Non-U.S. Plans | Common collective trusts | Level 1      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
Non-U.S. Plans | Common collective trusts | Level 2      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 386 327  
Non-U.S. Plans | Common collective trusts | Level 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
Non-U.S. Plans | Real estate funds | Fair Value, Inputs, Level 1, 2 and 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 61 60  
Non-U.S. Plans | Real estate funds | Level 1      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
Non-U.S. Plans | Real estate funds | Level 2      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 61 60  
Non-U.S. Plans | Real estate funds | Level 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
Non-U.S. Plans | Real estate funds | Fair Value Measured at Net Asset Value Per Share      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 23 23  
Non-U.S. Plans | Insurance contracts | Fair Value, Inputs, Level 1, 2 and 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 66 73  
Non-U.S. Plans | Insurance contracts | Level 1      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
Non-U.S. Plans | Insurance contracts | Level 2      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
Non-U.S. Plans | Insurance contracts | Level 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 66 73 72
Non-U.S. Plans | Other | Fair Value, Inputs, Level 1, 2 and 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 2 1  
Non-U.S. Plans | Other | Level 1      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
Non-U.S. Plans | Other | Level 2      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets 0 0  
Non-U.S. Plans | Other | Level 3      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan fair value of plan assets $ 2 $ 1 $ 2