XML 83 R115.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Employee benefit plans - Narrative (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Employee benefit plans      
Expense recorded $ 12 $ 12 $ 11
Aggregate accumulated benefit obligation 583 $ 519  
Pension      
Employee benefit plans      
Expected future contribution by the employer 20    
Other Postretirement      
Employee benefit plans      
Expected future contribution by the employer $ 1