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SIGNIFICANT ACCOUNTING POLICIES, Fair Value of Financial Instruments (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Fair value of financial instruments [Abstract]    
Transfers from Level 1 to Level 2 $ 0 $ 0
Transfers from Level 2 to Level 1 0 0
Transfers into (out of) Level 3 $ 0 $ 0