INVESTMENTS - Contractual and Economic Maturities of Investments in Fixed Maturities (Detail) - USD ($) $ in Millions		Dec. 31, 2018		Dec. 31, 2017
Available for sale:
Due in one year or less	[1]	$ 810
Due after one year through five years	[1]	8,313
Due after five years through 10 years	[1]	9,805
Due after 10 years	[1]	57,618
Mortgage- and asset-backed securities	[1]	310
Total fixed maturity securities, available for sale, amortized cost		76,856	[1],[2]	$ 75,132	[3]
Held to maturity:
Due in one year or less		180
Due after one year through five years		915
Due after five years through 10 years		927
Due after 10 years		28,282
Mortgage- and asset-backed securities		14
Total fixed maturity securities, held to maturity, amortized cost		30,318		31,430
Available for sale:
Due in one year or less	[1]	861
Due after one year through five years	[1]	8,312
Due after five years through 10 years	[1]	10,355
Due after 10 years	[1]	63,028
Mortgage- and asset-backed securities	[1]	339
Total fixed maturity securities, available for sale, fair value	[4],[5]	82,895	[1],[2]	84,313	[3]
Held to maturity:
Due in one year or less		182
Due after one year through five years		948
Due after five years through 10 years		1,004
Due after 10 years		34,573
Mortgage- and asset-backed securities		15
Total fixed maturity securities, held to maturity, fair value		$ 36,722		$ 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 ($1,139 at amortized cost and $1,140 at fair value)

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

[4] Includes perpetual securities

[5] Includes perpetual securities