XML 21 R62.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Debt - Summary of senior unsecured notes (Detail) - USD ($)
$ in Millions
12 Months Ended
Sep. 12, 2019
Dec. 31, 2019
Senior Unsecured Notes Series L [Member]    
Term 7 years  
Interest Rate 3.31%  
Face Value $ 200  
Maturity Date   Sep. 30, 2026
Senior Unsecured Notes Series M [Member]    
Term 10 years  
Interest Rate 3.53%  
Face Value $ 300  
Maturity Date   Sep. 30, 2029