Formation of Genworth and Basis of Presentation - Schedule of Impact of Correction In Balance Sheet (Detail) - USD ($) $ in Millions	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Jan. 01, 2021
Assets
Deferred tax asset	$ 1,954		$ 1,983				$ 3,776
Total assets	89,844		89,714				122,346
Liabilities:
Future policy benefits	56,443		55,407				84,786
Other liabilities	1,607		1,687				1,618
Total liabilities	81,577		81,328				120,269
Equity:
Accumulated other comprehensive income (loss)	(2,861)	$ (2,853)	(2,614)	$ (3,288)	$ (4,549)	$ (5,855)	(7,108)
Retained earnings	1,398		1,139				(626)
Total Genworth Financial, Inc.'s stockholders' equity	7,460		7,631				1,575
Total equity	8,267	$ 8,232	8,386	$ 7,232	$ 5,819	4,285	2,077
Total liabilities and equity	$ 89,844		89,714				122,346
Previously reported
Assets
Deferred tax asset			1,968				3,765
Total assets			89,699				122,335
Liabilities:
Future policy benefits			55,349				84,736
Other liabilities			1,675				1,618
Total liabilities			81,258				120,219
Equity:
Accumulated other comprehensive income (loss)			(2,617)				(7,126)
Retained earnings			1,197				(569)
Total Genworth Financial, Inc.'s stockholders' equity			7,686				1,614
Total equity			8,441				2,116
Total liabilities and equity			89,699				122,335
Correction impacts
Assets
Deferred tax asset			15				11
Total assets			15				11
Liabilities:
Future policy benefits			58				50
Other liabilities			12				0
Total liabilities			70				50
Equity:
Accumulated other comprehensive income (loss)			3			(5,855)	18
Retained earnings			(58)			$ 225	(57)
Total Genworth Financial, Inc.'s stockholders' equity			(55)				(39)
Total equity			(55)				(39)
Total liabilities and equity			$ 15				$ 11