Effects of Reinsurance on Premiums Written and Earned (Detail) - USD ($) $ in Millions			12 Months Ended
		Dec. 01, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Reinsurance [Abstract]
Direct, Written			$ 4,406	$ 4,456	$ 4,566
Assumed, Written			293	298	307
Ceded, Written			(1,117)	(1,118)	(1,528)
Net premiums, Written			3,582	3,636	3,345
Direct, Earned			4,460	4,500	4,627
Assumed, Earned			293	298	307
Ceded, Earned		$ (360)	(1,117)	(1,118)	(1,528)
Net premiums, Earned			$ 3,636	$ 3,680	$ 3,406
Percentage of amount assumed to net			8.00%	8.00%	9.00%
Life Insurance
Reinsurance [Abstract]
Direct, Written			$ 699	$ 738	$ 774
Assumed, Written			1	1	2
Ceded, Written	[1]		(493)	(505)	(913)
Direct, Earned			699	738	775
Assumed, Earned			1	1	2
Ceded, Earned	[1]		(493)	(505)	(913)
Accident and Health Insurance Product Line
Reinsurance [Abstract]
Direct, Written	[2]		2,712	2,739	2,802
Assumed, Written	[2]		288	294	302
Ceded, Written	[2]		(537)	(533)	(543)
Direct, Earned	[2]		2,712	2,739	2,802
Assumed, Earned	[2]		288	294	302
Ceded, Earned	[2]		(537)	(533)	(543)
Mortgage insurance
Reinsurance [Abstract]
Direct, Written			995	979	990
Assumed, Written			4	3	3
Ceded, Written			(87)	(80)	(72)
Direct, Earned			1,049	1,023	1,050
Assumed, Earned			4	3	3
Ceded, Earned			$ (87)	$ (80)	$ (72)

[1] Effective December 1, 2021 and included in the year ended December 31, 2021, we entered into a reinsurance agreement with SCOR Global Life USA Reinsurance Company, under which we ceded premiums of $360 million associated with certain term life insurance policies.

[2] Accident and health insurance is comprised of our long-term care insurance products.