FAIR VALUE MEASUREMENTS (Details - Assets measured at fair value on a non-recurring basis at the time of impairment and the related impairment charges recorded during the periods presented) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Fair Value Assets Impairment Charges Measured on Nonrecurring Basis [Domain]
Fair Value Assets Measured on Nonrecurring Basis [Line Items]
Fair Value	$ 89		$ 404
Other investments
Fair Value Assets Measured on Nonrecurring Basis [Line Items]
Fair Value	89		376
Other assets
Fair Value Assets Measured on Nonrecurring Basis [Line Items]
Fair Value	0		28
Level 1 | Fair Value Assets Impairment Charges Measured on Nonrecurring Basis [Domain]
Fair Value Assets Measured on Nonrecurring Basis [Line Items]
Fair Value	0		0
Level 1 | Other investments
Fair Value Assets Measured on Nonrecurring Basis [Line Items]
Fair Value	0		0
Level 1 | Other assets
Fair Value Assets Measured on Nonrecurring Basis [Line Items]
Fair Value	0		0
Level 2 | Fair Value Assets Impairment Charges Measured on Nonrecurring Basis [Domain]
Fair Value Assets Measured on Nonrecurring Basis [Line Items]
Fair Value	0		0
Level 2 | Other investments
Fair Value Assets Measured on Nonrecurring Basis [Line Items]
Fair Value	0		0
Level 2 | Other assets
Fair Value Assets Measured on Nonrecurring Basis [Line Items]
Fair Value	0		0
Level 3 | Fair Value Assets Impairment Charges Measured on Nonrecurring Basis [Domain]
Fair Value Assets Measured on Nonrecurring Basis [Line Items]
Fair Value	89		404
Level 3 | Other investments
Fair Value Assets Measured on Nonrecurring Basis [Line Items]
Fair Value	89		376
Level 3 | Other assets
Fair Value Assets Measured on Nonrecurring Basis [Line Items]
Fair Value	0		$ 28
Fair value on a non-recurring basis | Fair Value Assets Impairment Charges Measured on Nonrecurring Basis [Domain]
Fair Value Assets Measured on Nonrecurring Basis [Line Items]
Impairment Charges	6	$ 23
Fair value on a non-recurring basis | Other investments
Fair Value Assets Measured on Nonrecurring Basis [Line Items]
Impairment Charges	6	11
Fair value on a non-recurring basis | Other assets
Fair Value Assets Measured on Nonrecurring Basis [Line Items]
Impairment Charges	$ 0	$ 12