Retirement Benefits - Narrative (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended			9 Months Ended
	Feb. 28, 2025	Sep. 30, 2025	Mar. 31, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Compensation and Retirement Disclosure [Line Items]
Portion of pension and OPEB obligation attributed to disclosed plans (as a percent)					98.00%
Defined contribution plan expense, employer contribution		$ 39		$ 43	$ 120	$ 128
Defined Benefit Plan Purchase of Annuity Contract	$ 423
Pension Plan [Member]
Compensation and Retirement Disclosure [Line Items]
Settlements					82
Pension Plan [Member] | United States [Member]
Compensation and Retirement Disclosure [Line Items]
Defined benefit pension plans, employer contributions					0
Defined benefit plan, estimated future employer additional contributions, remainder of fiscal year		0			0
Settlements		1	$ 82	0	83	0
Pension Plan [Member] | United Kingdom [Member]
Compensation and Retirement Disclosure [Line Items]
Defined benefit pension plans, employer contributions					1
Defined benefit plan, estimated future employer additional contributions, remainder of fiscal year		1			1
Settlements		0		0	3	0
Pension Plan [Member] | Other Foreign Plans [Member]
Compensation and Retirement Disclosure [Line Items]
Defined benefit pension plans, employer contributions					6
Settlements		0		$ 0	0	$ 0
Pension Plan [Member] | Other Foreign Plans [Member] | Maximum [Member]
Compensation and Retirement Disclosure [Line Items]
Defined benefit plan, estimated future employer additional contributions, remainder of fiscal year		$ 1			$ 1