SIGNIFICANT ACCOUNTING POLICIES - Adoption of New Accounting Pronouncements (Details) - USD ($) $ in Millions	Jun. 30, 2020	Mar. 31, 2020	Jan. 01, 2020	Dec. 31, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' equity	$ 19,134	$ 21,640		$ 15,126	$ 16,388	$ 14,682	$ 15,432
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' equity	$ 12,995	$ 17,112		11,827	$ 13,293	$ 13,004	$ 13,989
Cumulative effect of period of adoption, adjusted balance
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' equity				(30)
Cumulative effect of period of adoption, adjusted balance | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' equity				$ (30)
Accounting Standards Update 2016-13 | Cumulative effect of period of adoption, adjusted balance | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' equity			$ (40)