INVESTMENTS - Contractual and Economic Maturities of Investments in Fixed Maturities (Detail) - USD ($) $ in Millions		Sep. 30, 2018		Dec. 31, 2017
Available for sale:
Due in one year or less	[1]	$ 691
Due after one year through five years	[1]	8,058
Due after five years through 10 years	[1]	10,282
Due after 10 years	[1]	56,916
Mortgage- and asset-backed securities	[1]	305
Total fixed maturity securities, available for sale, amortized cost		76,252	[1],[2]	$ 75,132	[3]
Held to maturity:
Due in one year or less		528
Due after one year through five years		541
Due after five years through 10 years		1,303
Due after 10 years		28,034
Mortgage- and asset-backed securities		15
Total fixed maturity securities, held to maturity, amortized cost		30,421		31,430
Available for sale:
Due in one year or less	[1]	757
Due after one year through five years	[1]	8,199
Due after five years through 10 years	[1]	10,936
Due after 10 years	[1]	62,071
Mortgage- and asset-backed securities	[1]	333
Total fixed maturity securities, available for sale, fair value	[4]	82,296	[1],[2]	84,313	[3]
Held to maturity:
Due in one year or less		533
Due after one year through five years		569
Due after five years through 10 years		1,415
Due after 10 years		33,718
Mortgage- and asset-backed securities		15
Total fixed maturity securities, held to maturity, fair value		$ 36,250		$ 38,072

[1] Includes perpetual securities, categorized in accordance with their respective economic maturities (the expected maturity date created by the combination of features in the financial instrument)

[2] Includes perpetual securities ($1,408 at amortized cost and $1,591 at fair value)

[3] Includes perpetual securities ($1,462 at amortized cost and $1,789 at fair value)

[4] Includes perpetual securities