FAIR VALUE MEASUREMENTS - Changes in Available-For-Sale Investments and Derivatives Classified as Level 3 (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017		Dec. 31, 2016
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period		$ 223		$ 58
Realized gains or losses included in earnings		42		195
Unrealized gains or losses included in other comprehensive income (loss)		5		15
Purchases		214		16
Issuances		0		0
Sales		(3)		0
Settlements		(26)		(61)
Transfers into Level 3		24		0
Transfers out of Level 3		(26)		0
Balance, end of period		453		223
Change in unrealized gain (losses) still held		42		195
Foreign currency swaps
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance, beginning of period	[1]	(21)		(192)
Realized gains or losses included in earnings	[1]	43		194
Unrealized gains or losses included in other comprehensive income (loss)	[1]	0		(22)
Purchases	[1]	0		0
Issuances	[1]	0		0
Sales	[1]	0		0
Settlements	[1]	0		(1)
Transfers into Level 3	[1]	0		0
Transfers out of Level 3	[1]	0		0
Balance, end of period	[1]	22		(21)
Change in unrealized gain (losses) still held	[1]	43		194
Credit default swaps
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance, beginning of period	[1]	2		1
Realized gains or losses included in earnings	[1]	(1)		1
Unrealized gains or losses included in other comprehensive income (loss)	[1]	0		0
Purchases	[1]	0		0
Issuances	[1]	0		0
Sales	[1]	0		0
Settlements	[1]	0		0
Transfers into Level 3	[1]	0		0
Transfers out of Level 3	[1]	0		0
Balance, end of period	[1]	1		2
Change in unrealized gain (losses) still held	[1]	(1)		1
Fixed maturities | Mortgage- and asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period		198		220
Realized gains or losses included in earnings		0		0
Unrealized gains or losses included in other comprehensive income (loss)		3		38
Purchases		0		0
Issuances		0		0
Sales		0		0
Settlements		(26)		(60)
Transfers into Level 3		0		0
Transfers out of Level 3		0		0
Balance, end of period		175		198
Change in unrealized gain (losses) still held		0		0
Fixed maturities | Public utilities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period		16		0
Realized gains or losses included in earnings		0		0
Unrealized gains or losses included in other comprehensive income (loss)		0		0
Purchases		76		16
Issuances		0		0
Sales		0		0
Settlements		0		0
Transfers into Level 3		0		0
Transfers out of Level 3		(24)	[2]	0
Balance, end of period		68		16
Change in unrealized gain (losses) still held		0		0
Fixed maturities | Banks/financial institutions
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period		25		26
Realized gains or losses included in earnings		0		0
Unrealized gains or losses included in other comprehensive income (loss)		0		(1)
Purchases		0		0
Issuances		0		0
Sales		0		0
Settlements		0		0
Transfers into Level 3		0		0
Transfers out of Level 3		0		0
Balance, end of period		25		25
Change in unrealized gain (losses) still held		0		0
Fixed maturities | Other corporate
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period		0		0
Realized gains or losses included in earnings		0		0
Unrealized gains or losses included in other comprehensive income (loss)		2		0
Purchases		122		0
Issuances		0		0
Sales		(2)		0
Settlements		0		0
Transfers into Level 3		24	[2]	0
Transfers out of Level 3		0		0
Balance, end of period		146		0
Change in unrealized gain (losses) still held		0		0
Equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period		3		3
Realized gains or losses included in earnings		0		0
Unrealized gains or losses included in other comprehensive income (loss)		0		0
Purchases		16		0
Issuances		0		0
Sales		(1)		0
Settlements		0		0
Transfers into Level 3		0		0
Transfers out of Level 3		(2)	[3]	0
Balance, end of period		16		3
Change in unrealized gain (losses) still held		$ 0		$ 0

[1] Derivative assets and liabilities are presented net

[2] Transfer due to sector classification change

[3] Transfer due to change in accounting method