Employee Benefit Plans - Domestic Operations and Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pension | U.S.
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 15	$ 22	$ 30
Interest cost	110	83	78
Expected return on plan assets	(123)	(108)	(134)
Curtailment	0	(10)	0
Settlement	(3)	17	3
Net amortization	14	19	25
Net periodic benefit cost	13	23	2
Pension | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Service cost	6	14	16
Interest cost	57	35	31
Expected return on plan assets	(80)	(92)	(111)
Settlement	0	0	10
Net amortization	26	24	55
Net periodic benefit cost	9	(19)	1
Other Postretirement
Defined Benefit Plan Disclosure [Line Items]
Service cost	8	11	12
Interest cost	30	20	19
Expected return on plan assets	(33)	(29)	(22)
Curtailment	0	0	0
Settlement	0	0	0
Net amortization	(2)	(1)	(3)
Net periodic benefit cost	$ 3	$ 1	$ 6