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Commitments And Contingencies (Tables)
3 Months Ended
Mar. 31, 2021
Commitments And Contingencies [Abstract]  
Commitments And Contingencies Activity Our personal injury liability activity was as follows:

Millions,

for the Three Months Ended March 31,

2021

2020 

Beginning balance

$

270 

$

265 

Current year accruals

18 

18 

Changes in estimates for prior years

21 

2 

Payments

(16)

(15)

Ending balance at March 31

$

293 

$

270 

Current portion, ending balance at March 31

$

60 

$

62 

Commitments And Contingencies Activity. Our environmental liability activity was as follows:

Millions,

for the Three Months Ended March 31,

2021

2020 

Beginning balance

$

233 

$

227 

Accruals

12 

15 

Payments

(11)

(16)

Ending balance at March 31

$

234 

$

226 

Current portion, ending balance at March 31

$

63 

$

64