NEW ACCOUNTING PRONOUNCEMENTS AND POLICIES - U.S. TAX REFORM (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Jun. 30, 2019	Jun. 30, 2018	Jan. 01, 2018
Income Tax Expense (Benefit)	$ 700	$ 1,472	$ 1,429	$ 2,353
U.S. Tax Cuts and Jobs Act, Effective 2018
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent						28.00%
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Base Rate, Percent							21.00%
Income Tax Expense (Benefit)		$ 628				$ 602
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Amount						3,800
Deferred Federal Income Tax Expense (Benefit)						$ 3,200
U.S. Tax Cuts and Jobs Act, Effective 2018 | Scenario, Forecast
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent					21.00%