INCOME TAXES - Federal Tax Reconciliation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Decrease in valuation allowance due to changes based on expiration or worthlessness of unutilized state net operating loss carryovers	$ 9	$ 28	$ 24
Income tax benefit, reduction in valuation allowance of expired or worthless operating loss carryforwards	9
Foreign pretax loss	6	70
Reconciliation between reported income tax expense (benefit) and income taxes calculated by the statutory federal income tax rate
Tax expense (benefit) at statutory federal rate of 21% in 2018 (35% in 2017 and 2016)	134	(35)	87
State income taxes, net of federal income tax benefit	23	4	16
Expired state net operating losses, net of federal income tax benefit	9	28	35
Tax attributable to noncontrolling interests	(70)	(113)	(106)
Nondeductible goodwill	8	109	29
Nontaxable gains	0	0	(11)
Nondeductible litigation costs	0	0	37
Impact of decrease in federal tax rate on deferred taxes	(1)	246	0
Reversal of permanent reinvestment assumption and other adjustments related to divestiture of foreign subsidiary	(6)	(30)	0
Stock-based compensation tax deficiencies	5	15	0
Changes in valuation allowance (including impact of decrease in federal tax rate)	76	0	(25)
Change in tax contingency reserves, including interest	(1)	(6)	(9)
Prior-year provision to return adjustments and other changes in deferred taxes	(5)	4	12
Other items	4	(3)	2
Income tax expense (benefit)	$ 176	$ 219	$ 67