INCOME TAXES - Effective Income Tax Rate Applicable (Details) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
	Feb. 08, 2019	Dec. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Expense Benefit Continuing Operations Income Tax Reconciliation [Abstract]
U.S. federal statutory income tax			$ 207	$ (45)	$ 170
State income taxes, net of federal tax benefit			23	(31)	8
REIT income not subject to federal income tax			(51)	(68)	(116)
SDT settlement	$ 21	$ 21	0	0	21
Voluntary pension contribution			0	0	(41)
Return to provision adjustment			(3)	4	(1)
Foreign taxes			11	(2)	15
Other, net			(2)	5	3
Total income tax provision (benefit)			$ 185	$ (137)	$ 59
Effective income tax rate			18.80%	64.10%	7.30%