Retirement Benefits (Components of the Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pension  Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 23	$ 28	$ 38
Interest cost	599	389	341
Expected return on plan assets	(860)	(778)	(832)
Amortization of prior service		1
Recognized actuarial loss (gain)	22	149	206
Net periodic benefit (credit) cost	(216)	(211)	(247)
Curtailment loss	0	0	2
Settlement loss	2	2	5
Net benefit (credit) cost	(214)	(209)	(240)
Pension  Benefits | United States (a)
Defined Benefit Plan Disclosure [Line Items]
Interest cost	260	193	184
Expected return on plan assets	(311)	(336)	(327)
Recognized actuarial loss (gain)	19	74	90
Net periodic benefit (credit) cost	(32)	(69)	(53)
Pension  Benefits | Non-U.S.
Defined Benefit Plan Disclosure [Line Items]
Service cost	23	28	38
Interest cost	339	196	157
Expected return on plan assets	(549)	(442)	(505)
Amortization of prior service	0	1	0
Recognized actuarial loss (gain)	3	75	116
Net periodic benefit (credit) cost	(184)	(142)	(194)
Curtailment loss	0	0	2
Settlement loss	2	2	5
Net benefit (credit) cost	(182)	(140)	(187)
Post-retirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	1
Interest cost	3	3	2
Expected return on plan assets	0	0	0
Amortization of prior service	(2)	(2)	(2)
Recognized actuarial loss (gain)	(3)	1	1
Net periodic benefit (credit) cost	(2)	2	2
Curtailment loss	0	0	0
Settlement loss	0	0	0
Net benefit (credit) cost	(2)	2	2
Post-retirement Benefits | United States (a)
Defined Benefit Plan Disclosure [Line Items]
Interest cost	1	1	1
Expected return on plan assets	0	0	0
Recognized actuarial loss (gain)	(2)	0	(1)
Net periodic benefit (credit) cost	(1)	1	0
Post-retirement Benefits | Non-U.S.
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	1
Interest cost	2	2	1
Expected return on plan assets	0	0	0
Amortization of prior service	(2)	(2)	(2)
Recognized actuarial loss (gain)	(1)	1	2
Net periodic benefit (credit) cost	(1)	1	2
Curtailment loss	0	0	0
Settlement loss	0	0	0
Net benefit (credit) cost	$ (1)	$ 1	$ 2