SHARE-BASED COMPENSATION PROGRAMS - Restricted and Performance Stock Activity (Details)	12 Months Ended
	Dec. 31, 2020 $ / shares shares
Holdings Restricted Stock | Restricted Stock Unit Awards
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Unvested, Beginning Balance (in shares) | shares	1,805,301
Granted (in shares) | shares	994,290
Forfeited (in shares) | shares	(117,353)
Vested (in shares) | shares	(629,202)
Unvested, Ending Balance (in shares) | shares	2,053,036
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Unvested, Beginning Balance, Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares	$ 19.35
Granted, Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares	22.85
Forfeited, Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares	20.36
Vested, Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares	19.81
Unvested, Ending Balance, Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares	$ 21.15
Holdings Restricted Stock | Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Unvested, Beginning Balance (in shares) | shares	383,641
Granted (in shares) | shares	225,674
Forfeited (in shares) | shares	(51,860)
Vested (in shares) | shares	0
Unvested, Ending Balance (in shares) | shares	557,455
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Unvested, Beginning Balance, Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares	$ 21.05
Granted, Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares	23.92
Forfeited, Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares	21.97
Vested, Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares
Unvested, Ending Balance, Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares	$ 22.12
AXA Restricted Stock | Restricted Stock Unit Awards
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Unvested, Beginning Balance (in shares) | shares	19,280
Granted (in shares) | shares	0
Forfeited (in shares) | shares	0
Vested (in shares) | shares	(19,280)
Unvested, Ending Balance (in shares) | shares	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Unvested, Beginning Balance, Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares	$ 19.20
Granted, Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares	0
Forfeited, Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares	0
Vested, Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares	19.20
Unvested, Ending Balance, Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares	$ 0
AXA Restricted Stock | Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Unvested, Beginning Balance (in shares) | shares	2,154,059
Granted (in shares) | shares	0
Forfeited (in shares) | shares	(62,493)
Vested (in shares) | shares	(1,074,313)
Unvested, Ending Balance (in shares) | shares	1,017,254
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Unvested, Beginning Balance, Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares	$ 20.08
Granted, Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares	0
Forfeited, Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares	20.74
Vested, Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares	18.91
Unvested, Ending Balance, Weighted Average Grant Date Fair Value (in dollars per share) | $ / shares	$ 21.28