Employee Benefit Plans - PAC - Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
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)
Settlement	0	0	0
Net amortization	(2)	(1)	(3)
Net periodic benefit cost	3	1	6
Other Postretirement | PAC
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	2	2
Interest cost	11	8	7
Expected return on plan assets	(13)	(11)	(9)
Settlement	0	0	0
Net amortization	(2)	1	1
Net periodic benefit cost	(3)	0	1
U.S. | Pension
Defined Benefit Plan Disclosure [Line Items]
Service cost	15	22	30
Interest cost	110	83	78
Expected return on plan assets	(123)	(108)	(134)
Settlement	(3)	17	3
Net amortization	14	19	25
Net periodic benefit cost	13	23	2
U.S. | Pension | PAC
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0
Interest cost	39	29	29
Expected return on plan assets	(49)	(42)	(51)
Settlement	0	6	6
Net amortization	12	16	21
Net periodic benefit cost	2	9	5
Settlement losses, gross	0	24	15
Settlement losses, regulatory deferrals	$ 0	$ 18	$ 9