XML 69 R41.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Summary of Significant Accounting Policies - Goodwill and intangible assets (Details) - USD ($)
$ in Millions
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Goodwill and intangible assets      
Goodwill $ 801 $ 791 $ 803