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Retirement Benefits - Narrative (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Feb. 28, 2025	Mar. 31, 2026	Mar. 31, 2025
Compensation and Retirement Disclosure [Line Items]
Portion of pension and OPEB obligation attributed to disclosed plans (as a percent)		98.00%
Defined contribution plan expenses		$ 41	$ 40
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
Settlements		0	82
Pension Plan [Member] \| United Kingdom [Member]
Compensation and Retirement Disclosure [Line Items]
Defined benefit plan, estimated future employer additional contributions, remainder of fiscal year		1
Settlements		0	3
Pension Plan [Member] \| United Kingdom [Member] \| Maximum [Member]
Compensation and Retirement Disclosure [Line Items]
Defined benefit pension plans, employer contributions		1
Pension Plan [Member] \| Other Foreign Plans [Member]
Compensation and Retirement Disclosure [Line Items]
Defined benefit plan, estimated future employer additional contributions, remainder of fiscal year		1
Settlements		3	$ 0
Pension Plan [Member] \| Other Foreign Plans [Member] \| Maximum [Member]
Compensation and Retirement Disclosure [Line Items]
Defined benefit pension plans, employer contributions		$ 1