XML 36 R104.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Derivative Assets And Liabilities (Derivatives Recognized OCI On Derivatives) (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Cost of Sales [Member] | Commodity Derivatives [Member]      
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net $ 0 $ (3) $ 26