ACQUISITIONS AND DIVESTITURES - Narrative (Details) $ in Millions					3 Months Ended	9 Months Ended
	Jul. 11, 2018 USD ($) location State	Jul. 02, 2018 USD ($)	Apr. 10, 2018 USD ($)	Mar. 01, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Aug. 09, 2018 USD ($)	Dec. 31, 2017 USD ($)
Business Acquisition [Line Items]
Payments to acquire equity method investments						$ 1,095	$ 0
Equity method investment in Kindred at Home						1,048			$ 0
Goodwill, acquired during period						614
MCCI
Business Acquisition [Line Items]
Notes receivable and revolving note, related party				$ 383
MCCI
Business Acquisition [Line Items]
Payments to acquire business				169
Goodwill, acquired during period				479
Other intangible assets acquired				80
Net tangible assets acquired				$ 27
Other intangible assets, weighted average useful life				8 years
FPG
Business Acquisition [Line Items]
Payments to acquire business			$ 185
Goodwill, acquired during period			135
Other intangible assets acquired			38
Net tangible assets acquired			$ 17
Other intangible assets, weighted average useful life			4 years 10 months 25 days
KMG America Corporation | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Business Acquisition [Line Items]
Parent company cash contributed to sale of subsidiary								$ 190
Transfer of statutory capital with sale of subsidiary								$ 160
Pretax loss on sale of subsidiary						786
Tax benefit on sale of subsidiary						430
Disposal group, revenue					$ 66	182	199
Disposal group, pretax income (loss)					$ (5)	47	$ (15)
KIC
Business Acquisition [Line Items]
Payments for reinsurance						245
Kindred at Home
Business Acquisition [Line Items]
Equity method investment, ownership percentage		40.00%
Payments to acquire equity method investments		$ 850
Equity method investment in Kindred at Home		1,000
Curo Health Services
Business Acquisition [Line Items]
Equity method investment, ownership percentage	40.00%
Payments to acquire equity method investments	$ 250
Equity method investment, number of locations | location	245
Equity method investment, number of states | State	22
Equity Option | Put Option
Business Acquisition [Line Items]
Purchase price allocation, financial asset		236
Equity Option | Put Option | Other long-term assets
Business Acquisition [Line Items]
Financial asset, fair value						221
Equity Option | Call Option
Business Acquisition [Line Items]
Purchase price allocation, financial liability		$ 291
Equity Option | Call Option | Other long-term liabilities
Business Acquisition [Line Items]
Financial liability, fair value						$ 265