XML 85 R74.htm IDEA: XBRL DOCUMENT v3.21.2
Benefit Plans - Postretirement Benefit Plans (Details) - Postretirement Benefit Plans - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2021
Jun. 30, 2020
Jun. 30, 2021
Jun. 30, 2020
Defined Benefit Plan Disclosure [Line Items]        
Service cost $ 1 $ 2 $ 2 $ 3
Interest cost 2 3 4 6
Net loss from experience differences 0 1 1 4
Prior service credit 0 (7) 0 (15)
Net periodic benefit cost (credit) $ 3 $ (1) $ 7 $ (2)