XML 49 R6.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($)
$ in Millions
Dec. 31, 2019
Dec. 31, 2018
Statement of Financial Position [Abstract]    
Allowance for doubtful accounts $ 13 $ 11
Accumulated depreciation $ 1,825 $ 1,021