INVESTMENTS (AVAILABLE FOR SALE SECURITIES) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 34,988	$ 32,236
Gross Unrealized Gains	1,774	1,306
Gross Unrealized Losses	247	859
Fair Value	36,515	32,683
OTTI in AOCI	2	10
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Subtotal, Fair Value	36,358	32,570
Available For Sale Fixed Maturities Proceeds Gross Gains And Gross Losses From Sales And Other Than Temporary Impairments [Abstract]
Proceeds from sales	7,232	4,324	$ 979
Gross gains on sales	98	111	33
Gross losses on sales	(211)	(58)	(8)
Total other-than-temporary impairment losses	(13)	(65)	(41)
Non-credit losses recognized in OCI	0	0	0
Net impairment losses recognized	(13)	(65)	(41)
Fixed Maturities - Credit Loss Impairments
Recognized impairments on securities impaired to fair value this period	0	(17)
Increases due to passage of time on previously recorded credit losses	0	0
Accretion of previously recognized impairments due to increases in expected cash flows	0	0
Public corporate
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	13,645	12,418
Gross Unrealized Gains	725	675
Gross Unrealized Losses	25	81
Fair Value	14,345	13,012
OTTI in AOCI	0	0
Private corporate
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	6,951	6,880
Gross Unrealized Gains	217	215
Gross Unrealized Losses	31	55
Fair Value	7,137	7,040
OTTI in AOCI	0	0
U.S. Treasury, government and agency
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	12,644	10,739
Gross Unrealized Gains	676	221
Gross Unrealized Losses	185	624
Fair Value	13,135	10,336
OTTI in AOCI	0	0
States and political subdivisions
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	414	432
Gross Unrealized Gains	67	63
Gross Unrealized Losses	0	2
Fair Value	481	493
OTTI in AOCI	0	0
Foreign governments
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	387	375
Gross Unrealized Gains	27	29
Gross Unrealized Losses	5	14
Fair Value	409	390
OTTI in AOCI	0	0
Commercial mortgage-backed
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	0	415
Gross Unrealized Gains	0	28
Gross Unrealized Losses	0	72
Fair Value	0	371
OTTI in AOCI	0	7
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Amortized Cost Basis, without Single Maturity Date	0
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Fair Value, without Single Maturity Date	0
Residential mortgage-backed
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	236	294
Gross Unrealized Gains	15	20
Gross Unrealized Losses	0	0
Fair Value	251	314
OTTI in AOCI	0	0
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Amortized Cost Basis, without Single Maturity Date	236
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Fair Value, without Single Maturity Date	251
Asset-backed
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	93	51
Gross Unrealized Gains	3	10
Gross Unrealized Losses	0	1
Fair Value	96	60
OTTI in AOCI	2	3
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Amortized Cost Basis, without Single Maturity Date	93
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Fair Value, without Single Maturity Date	96
Redeemable preferred stock
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	461	519
Gross Unrealized Gains	44	45
Gross Unrealized Losses	1	10
Fair Value	504	554
OTTI in AOCI	0	0
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Amortized Cost Basis, without Single Maturity Date	461
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Fair Value, without Single Maturity Date	504
Fixed maturities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	34,831	32,123
Gross Unrealized Gains	1,774	1,306
Gross Unrealized Losses	247	859
Fair Value	36,358	32,570
OTTI in AOCI	2	10
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Due in one year or less, Amortized Cost	1,339
Due in years two through five, Amortized Cost	7,773
Due in years six through ten, Amortized Cost	9,889
Due after ten years, Amortized Cost	15,040
Subtotal, Amortized Cost Basis	34,041
Amortized Cost Basis, without Single Maturity Date	34,831
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Due in one year or less, Fair Value	1,352
Due in years two through five, Fair Value	8,035
Due in years six through ten, Fair Value	10,136
Due after ten years, Fair Value	15,984
Subtotal, Fair Value	35,507
Fair Value, without Single Maturity Date	36,358
Fixed Maturities - Credit Loss Impairments
Balance beginning of period	(190)	(198)
Previously recognized impairments on securities that matured, paid, prepaid or sold	193	73
Impairments recognized this period on securities not previously impaired	(13)	(46)
Additional impairments this period on securities previously impaired	0	(2)
Balances at December 31,	(10)	(190)	$ (198)
Equity securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	157	113
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	157	113
OTTI in AOCI	$ 0	$ 0