Retirement Benefits - Accumulated Benefit Obligation In Excess of Plan Assets (Details) - Pension Plan [Member] - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
United States [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	$ 4,098	$ 939
Accumulated benefit obligation at end of year	4,098	939
Fair value of plan assets at end of year	3,803	713
United Kingdom [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	5	5
Accumulated benefit obligation at end of year	5	5
Fair value of plan assets at end of year	0	0
Other Foreign Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	324	238
Accumulated benefit obligation at end of year	309	228
Fair value of plan assets at end of year	$ 182	$ 106