XML 86 R65.htm IDEA: XBRL DOCUMENT v3.20.4
Property and Equipment - Narrative (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Property, Plant and Equipment [Abstract]    
Depreciation expense $ 42 $ 41
Impairment charges $ 12 $ 4