Employee Benefit Plans - PAC - Funded Status (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Other Postretirement
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance	$ 744	$ 742
Employer contributions	14	3
Participant contributions	9	8
Actual return on plan assets	53	40
Settlement	0	0
Benefits paid	(51)	(49)
Ending balance	769	744	$ 742
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning balance	758	673
Service cost	12	7	8
Interest cost	19	21	27
Participant contributions	9	8
Actuarial (gain) loss	(35)	61
Settlement	0	0
Benefits Paid	(51)	(49)
Ending balance	714	758	673
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Plan assets at fair value, end of year	769	744	742
Benefit obligation, end of year	714	758	673
Funded status	55	(14)
Other assets	60	20
Other current liabilities	0	0
Other long-term liabilities	(5)	(34)
Amounts recognized	55	(14)
Supplemental Employee Retirement Plan
Defined Benefit Plans, Supplemental Employee Retirement Plans [Abstract]
Rabbi trusts	343	303
PAC | Other Postretirement
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance	327	334
Employer contributions	1	0
Participant contributions	6	4
Actual return on plan assets	14	15
Settlement	0	0
Benefits paid	(24)	(26)
Ending balance	324	327	334
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning balance	307	304
Service cost	2	2	2
Interest cost	7	9	12
Participant contributions	6	4
Actuarial (gain) loss	(10)	14
Settlement	0	0
Benefits Paid	(24)	(26)
Ending balance	288	307	304
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Plan assets at fair value, end of year	324	327	334
Benefit obligation, end of year	288	307	304
Funded status	36	20
Other assets	36	20
Other current liabilities	0	0
Other long-term liabilities	0	0
Amounts recognized	36	20
PAC | Supplemental Employee Retirement Plan
Defined Benefit Plans, Supplemental Employee Retirement Plans [Abstract]
Rabbi trusts	69	61
United States | Pension
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance	2,824	2,656
Employer contributions	13	13
Participant contributions	0	0
Actual return on plan assets	234	373
Settlement	(134)	0
Benefits paid	(142)	(218)
Ending balance	2,795	2,824	2,656
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning balance	3,077	2,878
Service cost	30	17	16
Interest cost	78	93	111
Participant contributions	0	0
Actuarial (gain) loss	(132)	226
Settlement	(134)	0
Benefits Paid	(142)	(218)
Ending balance	2,777	3,077	2,878
Accumulated benefit obligation, end of year	2,713	2,999
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Plan assets at fair value, end of year	2,795	2,824	2,656
Benefit obligation, end of year	2,777	3,077	2,878
Funded status	18	(253)
Other assets	204	43
Other current liabilities	(13)	(13)
Other long-term liabilities	(173)	(283)
Amounts recognized	18	(253)
United States | PAC | Pension
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance	1,064	1,036
Employer contributions	5	5
Participant contributions	0	0
Actual return on plan assets	109	124
Settlement	(52)	0
Benefits paid	(68)	(101)
Ending balance	1,058	1,064	1,036
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning balance	1,202	1,167
Service cost	0	0	0
Interest cost	29	36	44
Participant contributions	0	0
Actuarial (gain) loss	(63)	100
Settlement	(52)	0
Benefits Paid	(68)	(101)
Ending balance	1,048	1,202	1,167
Accumulated benefit obligation, end of year	1,048	1,202
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Plan assets at fair value, end of year	1,058	1,064	1,036
Benefit obligation, end of year	1,048	1,202	$ 1,167
Funded status	10	(138)
Other assets	63	8
Other current liabilities	(4)	(4)
Other long-term liabilities	(49)	(142)
Amounts recognized	$ 10	$ (138)