BASIS OF PRESENTATION (Details) $ / shares in Units, $ in Millions			3 Months Ended
	Nov. 25, 2019	Nov. 13, 2018 USD ($)	Mar. 31, 2020 USD ($) item $ / shares	Mar. 31, 2019 USD ($)	Dec. 31, 2019 $ / shares
Basis of Presentation [Line Items]
Common stock, par value (in dollars per share) | $ / shares			$ 2.50		$ 2.5
Income (loss) from divested businesses			$ (216)	$ 6
Fortitude Holdings | Fortitude RE
Basis of Presentation [Line Items]
Parent owneship interest		100.00%
American International Group, Inc. | Fortitude Holdings
Basis of Presentation [Line Items]
Percentage of common stock held after closing of transaction	3.50%
Carlyle FRL | Fortitude Holdings
Basis of Presentation [Line Items]
Voting interest in subsidiary, percent	51.60%
T&D | Fortitude Holdings
Basis of Presentation [Line Items]
Voting interest in subsidiary, percent	25.00%
Fortitude Holdings
Basis of Presentation [Line Items]
Consideration in cash		$ 381
Contingent considiration receivable			95
Contingent consideration receivable, maximum			$ 100
Planned distribution term			36 months
Expected payment to affiliates			$ 1,450
Maximum purchase price adjustment payable			500
Fortitude Holdings | TC Group Cayman
Basis of Presentation [Line Items]
Voting interest in subsidiary, percent		19.90%
Fortitude Holdings | American International Group, Inc.
Basis of Presentation [Line Items]
Percentage of common stock held after closing of transaction		80.10%
Blackboard U.S. Holdings, Inc
Basis of Presentation [Line Items]
Income (loss) from divested businesses			$ (210)
Minimum
Basis of Presentation [Line Items]
Number of countries in which the entity operates | item			80