Pension and Other Postretirement Benefits - Schedule of Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Settlements		$ 5	$ 58	$ 75
Pension benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost		3	4	4
Interest cost		80	51	47
Expected return on plan assets		(74)	(80)	(90)
Recognized net actuarial loss (gain)		28	49	56
Amortization of prior service cost (benefit)		0	0	1
Settlements	$ 3	5	58	69
Curtailment		0	0	6
Net periodic benefit cost		42	82	93
Pension benefits | United States
Defined Benefit Plan Disclosure [Line Items]
Settlements			41
Net periodic benefit cost		40	79	61
Other postretirement benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost		1	2	2
Interest cost		7	4	5
Expected return on plan assets		0	0	0
Recognized net actuarial loss (gain)		(3)	1	0
Amortization of prior service cost (benefit)		(9)	(9)	(9)
Settlements		0	0	0
Curtailment		0	0	0
Net periodic benefit cost		$ (4)	$ (2)	(2)
Decrease in net periodic benefit cost for the recognition of the federal subsidy awarded under Medicare Part D (less than $1)				$ 1