Net Investment Gains (Losses) (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2021	Mar. 31, 2020
Available-for-sale fixed maturity securities:
Realized gains		$ 7	$ 2
Realized losses		(3)	0
Net realized gains (losses) on available-for-sale fixed maturity securities		4	2
Net change in allowance for credit losses on available-for-sale fixed maturity securities		(2)	0
Write-down of available-for-sale fixed maturity securities	[1]	(1)	0
Net realized gains (losses) on equity securities sold		(5)	0
Net unrealized gains (losses) on equity securities still held		(8)	(12)
Limited partnerships		37	(40)
Commercial mortgage loans		(1)	0
Derivative instruments	[2]	8	(48)
Other		1	(1)
Total net investment gains (losses)		$ 33	$ (99)

[1] Represents write-down of securities deemed uncollectible or that we intend to sell or will be required to sell prior to recovery of the amortized cost basis.

[2] See note 5 for additional information on the impact of derivative instruments included in net investment gains (losses).