XML 97 R81.htm IDEA: XBRL DOCUMENT v3.20.4
Share-based Compensation and Employee Benefits - Benefit Obligation, Plan Assets and Funded Status (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Pension Benefits      
Change in benefit obligation:      
Benefit obligation at beginning of period $ 2,696 $ 2,566  
Service cost 59 53 $ 52
Interest cost 71 96 84
Actuarial loss (gain) 198 159  
Benefits paid (180) (178)  
Participant contributions 0 0  
Medicare Part D subsidy receipts 0 0  
Benefit obligation at end of period 2,844 2,696 2,566
Change in plan assets:      
Fair value of plan assets at beginning of period 2,076 1,864  
Actual return on plan assets 178 330  
Employer contributions 125 60  
Participant contributions 0 0  
Medicare Part D subsidy receipts 0 0  
Benefits paid (180) (178)  
Fair value of plan assets at end of period 2,199 2,076 1,864
Funded status - net (liability) asset at December 31, (645) (620)  
OPEB      
Change in benefit obligation:      
Benefit obligation at beginning of period 333 339  
Service cost 1 1 1
Interest cost 8 12 12
Actuarial loss (gain) (17) 10  
Benefits paid (29) (32)  
Participant contributions 2 2  
Medicare Part D subsidy receipts 1 1  
Benefit obligation at end of period 299 333 339
Change in plan assets:      
Fair value of plan assets at beginning of period 333 306  
Actual return on plan assets 47 49  
Employer contributions 7 7  
Participant contributions 2 2  
Medicare Part D subsidy receipts 1 1  
Benefits paid (29) (32)  
Fair value of plan assets at end of period 361 333 $ 306
Funded status - net (liability) asset at December 31, $ 62 $ 0