Commitments and Contingencies Personal Injury (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Loss Contingency Accrual [Roll Forward]
Beginning balance	$ 110
Ending balance	120	$ 110
Personal Injury
Loss Contingency Accrual [Roll Forward]
Beginning balance	273	275	$ 308
Accruals / changes in estimates	61	45	80
Payments	(38)	(47)	(113)
Ending balance	296	273	275
Current portion of ending balance	85	$ 75	$ 75
Personal Injury \| Minimum
Loss Contingency Accrual [Roll Forward]
Future costs to settle claims and associated liability	250
Personal Injury \| Maximum
Loss Contingency Accrual [Roll Forward]
Future costs to settle claims and associated liability	$ 355

Amount of expense for newly incurred loss contingencies and revisions to previously reported estimates

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- Definition

Amount of loss contingency liability.

+ References

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Amount of loss contingency liability expected to be resolved within one year or the normal operating cycle, if longer.

+ References

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Amount of cash outflow reducing loss contingency liability.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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