Employee Benefit Plans - PAC - Funded Status (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Other Postretirement
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance	$ 614	$ 769
Employer contributions	6	8
Participant contributions	8	8
Actual return on plan assets	86	(122)
Settlement	0	0
Benefits paid	(49)	(49)
Ending balance	665	614	$ 769
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning balance	569	714
Service cost	8	11	12
Interest cost	30	20	19
Participant contributions	8	8
Actuarial gain (loss)	(1)	(155)
Settlement	0	0
Benefits Paid	(49)	(49)
Ending balance	565	569	714
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Plan assets at fair value, end of year	665	614	769
Benefit obligation, end of year	565	569	714
Funded status	100	45
Other assets	104	52
Other current liabilities	0	0
Other long-term liabilities	(4)	(7)
Amounts recognized	100	45
Supplemental Employee Retirement Plan
Defined Benefit Plans, Supplemental Employee Retirement Plans [Abstract]
Rabbi trusts	341	300
PAC | Other Postretirement
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance	264	324
Employer contributions	0	0
Participant contributions	4	5
Actual return on plan assets	25	(42)
Settlement	0	0
Benefits paid	(22)	(23)
Ending balance	271	264	324
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning balance	219	288
Service cost	1	2	2
Interest cost	11	8	7
Participant contributions	4	5
Actuarial gain (loss)	2	(61)
Settlement	0	0
Benefits Paid	(22)	(23)
Ending balance	215	219	288
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Plan assets at fair value, end of year	271	264	324
Benefit obligation, end of year	215	219	288
Funded status	56	45
Other assets	56	45
Other current liabilities	0	0
Other long-term liabilities	0	0
Amounts recognized	56	45
PAC | Supplemental Employee Retirement Plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Accumulated benefit obligation, end of year	41	42
Defined Benefit Plans, Supplemental Employee Retirement Plans [Abstract]
Rabbi trusts	68	61
U.S. | Pension
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance	2,013	2,795
Employer contributions	14	14
Participant contributions	0	0
Actual return on plan assets	219	(491)
Settlement	0	(164)
Benefits paid	(177)	(141)
Ending balance	2,069	2,013	2,795
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning balance	2,040	2,777
Service cost	15	22	30
Interest cost	110	83	78
Participant contributions	0	0
Actuarial gain (loss)	62	(524)
Settlement	0	(164)
Benefits Paid	(177)	(141)
Ending balance	2,050	2,040	2,777
Accumulated benefit obligation, end of year	2,013	2,003
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Plan assets at fair value, end of year	2,069	2,013	2,795
Benefit obligation, end of year	2,050	2,040	2,777
Funded status	19	(27)
Other assets	160	125
Other current liabilities	(13)	(13)
Other long-term liabilities	(128)	(139)
Amounts recognized	19	(27)
U.S. | PAC | Pension
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance	758	1,058
Employer contributions	4	4
Participant contributions	0	0
Actual return on plan assets	73	(172)
Settlement	0	(67)
Benefits paid	(71)	(65)
Ending balance	764	758	1,058
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning balance	746	1,048
Service cost	0	0	0
Interest cost	39	29	29
Participant contributions	0	0
Actuarial gain (loss)	26	(199)
Settlement	0	(67)
Benefits Paid	(71)	(65)
Ending balance	740	746	1,048
Accumulated benefit obligation, end of year	740	746
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Plan assets at fair value, end of year	764	758	1,058
Benefit obligation, end of year	740	746	$ 1,048
Funded status	24	12
Other assets	65	53
Other current liabilities	(4)	(4)
Other long-term liabilities	(37)	(37)
Amounts recognized	$ 24	$ 12