INSURANCE LIABILITIES AND ANNUITY BENEFITS - Schedule of Investment Contracts, Insurance Liabilities and Insurance Annuity Benefits (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Liability for Claims and Claims Adjustment Expense [Line Items]
Future policy benefit reserves	$ 30,508	$ 32,104
Other adjustments	4,051	5,655
Claim reserves	5,666	5,615
Investment contracts	2,169	2,191
Unearned premiums and other	385	322
Future policy benefit reserves, investment contracts, claim reserves and unearned premiums and other	38,729	40,232
Eliminations	(488)	(406)
Total	38,241	39,826
Long-term care insurance contracts
Liability for Claims and Claims Adjustment Expense [Line Items]
Future policy benefit reserves	16,785	16,755
Claim reserves	4,314	4,238
Investment contracts	0	0
Unearned premiums and other	26	30
Future policy benefit reserves, investment contracts, claim reserves and unearned premiums and other	21,125	21,023
Total	21,125	21,023
Structured settlement annuities & life insurance contracts
Liability for Claims and Claims Adjustment Expense [Line Items]
Future policy benefit reserves	9,491	9,511
Claim reserves	253	252
Investment contracts	1,112	1,136
Unearned premiums and other	194	196
Future policy benefit reserves, investment contracts, claim reserves and unearned premiums and other	11,050	11,095
Total	11,050	11,095
Other contracts
Liability for Claims and Claims Adjustment Expense [Line Items]
Future policy benefit reserves	181	183
Claim reserves	1,099	1,125
Investment contracts	1,057	1,055
Unearned premiums and other	165	96
Future policy benefit reserves, investment contracts, claim reserves and unearned premiums and other	2,502	2,459
Eliminations	(488)	(406)
Total	$ 2,014	$ 2,053