For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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Amount of contribution received by defined benefit plan from employer which increases plan assets.

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Amount of cost for defined contribution plan.

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Retirement Benefits (Narrative) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
	Dec. 31, 2023	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer		$ 16	$ 26	$ 67	$ 73
Estimated future employer contributions in current fiscal year		25		25
United States
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, cost recognized		45	45	142	133
United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, cost recognized		$ 39	$ 39	$ 130	$ 120
United Kingdom \| Defined Benefit Plan Assets Benchmark \| Geographic Concentration Risk
Defined Benefit Plan Disclosure [Line Items]
Concentration risk percentage (as a percent)	79.00%
Equity Funds \| United States
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation, percentage (as a percent)		50.00%		50.00%
Actual asset allocation percentage of equity (as a percent)		50.00%		50.00%
Equity Funds \| United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation, percentage (as a percent)		13.00%		13.00%
Actual asset allocation percentage of equity (as a percent)		14.00%		14.00%
Fixed Income Funds \| United States
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation, percentage (as a percent)		50.00%		50.00%
Actual asset allocation percentage of equity (as a percent)		50.00%		50.00%
Fixed Income Funds \| United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation, percentage (as a percent)		87.00%		87.00%
Actual asset allocation percentage of equity (as a percent)		86.00%		86.00%