ESTIMATES, SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES AND BALANCE SHEET DETAIL Estimates, Significant Accounting Policies and Balance Sheet Detail - Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member]
Investments, Fair Value Disclosure	$ 22	$ 20
Fair Value, Inputs, Level 1 [Member] | Available-for-sale Securities [Member]
Investments, Fair Value Disclosure	34	31
Fair Value, Inputs, Level 2 [Member] | Fixed Income Securities [Member]
Investments, Fair Value Disclosure	$ 12	$ 11