Employee Benefit Plans - 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
Amendment	2	0
Settlement	0	0
Acquisition	0	37
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)
Defined Benefit Plan, Pension Plan with Project Benefit Obligation in Excess of Plan Assets [Abstract]
Fair value of plan assets	137	417
Projected benefit obligation	142	451
Supplemental Employee Retirement Plan
Defined Benefit Plans, Supplemental Employee Retirement Plans [Abstract]
Rabbi trusts	343	303
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
Amendment	0	0
Settlement	(134)	0
Acquisition	0	81
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)
Defined Benefit Plan, Pension Plan with Project Benefit Obligation in Excess of Plan Assets [Abstract]
Fair value of plan assets	0	1,782
Projected benefit obligation	186	2,069
Fair value of plan assets	0	1,064
Accumulated benefit obligation	185	1,341
United Kingdom | Pension
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance	2,334	2,151
Employer contributions	28	56
Participant contributions	1	1
Actual return on plan assets	148	181
Settlement	(51)	(63)
Benefits paid	(72)	(67)
Foreign currency exchange rate changes	(25)	75
Ending balance	2,363	2,334	2,151
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning balance	2,205	2,019
Service cost	16	16	16
Interest cost	31	40	49
Participant contributions	1	1
Actuarial (gain) loss	(105)	188
Settlement	(51)	(63)
Benefits paid	(72)	(67)
Foreign currency exchange rate changes	(22)	71
Ending balance	2,003	2,205	2,019
Accumulated benefit obligation, end of year	1,778	1,963
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Plan assets at fair value, end of year	2,363	2,334	2,151
Benefit obligation, end of year	2,003	2,205	$ 2,019
Funded status	360	129
Other assets	$ 360	$ 129