Summary Of Adoption Of New Accounting Guidance Related To The Recognition And Measurement Of Long-Duration Insurance Contracts (Detail) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Jan. 01, 2021	Dec. 31, 2020
Assets
Total investments	$ 59,751	$ 58,948		$ 74,701
Cash, cash equivalents and restricted cash	2,215	1,799	$ 1,571	2,561
Accrued investment income	647	643		655
Deferred acquisition costs	1,988	2,211	2,488	2,809
Intangible assets	198	203		271
Reinsurance recoverable	19,054	19,059		28,135
Less: Allowance for credit losses	(29)	(63)	(58)	(45)	$ (45)
Reinsurance recoverable, net	19,025	18,996		28,090
Other assets	489	488		563
Deferred tax asset	1,952	1,983		3,776
Market risk benefit assets	43	26		22
Separate account assets	4,509	4,417		6,081
Assets related to discontinued operations				2,817
Total assets	90,817	89,714		122,346
Liabilities:
Future policy benefits	57,655	55,407		84,786
Policyholder account balances	15,540	16,564		19,633
Market risk benefit liabilities	625	748		1,310
Liability for policy and contract claims	652	683	819	761	761
Unearned premiums	149	203		307
Other liabilities	1,768	1,687		1,618
Long-term borrowings	1,584	1,611		3,403
Separate account liabilities	4,509	4,417	6,066	6,081	6,081
Liabilities related to discontinued operations	0	8		2,370
Total liabilities	82,482	81,328		120,269
Commitments and contingencies
Equity:
Class A common stock	1	1		1
Additional paid-in capital	11,884	11,869		12,008
Accumulated other comprehensive income (loss)	(2,555)	(2,614)	(5,855)	(7,108)	(7,108)
Retained earnings	1,213	1,139		(626)
Treasury stock, at cost	(3,063)	(2,764)		(2,700)
Total Genworth Financial, Inc.'s stockholders' equity	7,480	7,631		1,575
Noncontrolling interests	855	755		502
Total equity	8,335	8,386	$ 4,285	2,077
Total liabilities and equity	$ 90,817	89,714		122,346
Cumulative effect of change in accounting
Equity:
Total equity					(13,743)
Cumulative effect of change in accounting | Accounting Standards Update 2018-12
Equity:
Accumulated other comprehensive income (loss)				(11,500)
Retained earnings				(2,200)
Total equity				(13,700)
Cumulative effect of change in accounting | Eliminate shadow adjustments | Accounting Standards Update 2018-12
Assets
Total investments				0
Cash, cash equivalents and restricted cash				0
Accrued investment income				0
Deferred acquisition costs				1,322
Intangible assets				114
Reinsurance recoverable				0
Less: Allowance for credit losses				0
Reinsurance recoverable, net				0
Other assets				0
Deferred tax asset				(1,515)
Market risk benefit assets				0
Separate account assets				0
Assets related to discontinued operations				0
Total assets				(79)
Liabilities:
Future policy benefits				(4,456)
Policyholder account balances				(1,229)
Market risk benefit liabilities				0
Liability for policy and contract claims				0
Unearned premiums				0
Other liabilities				0
Long-term borrowings				0
Separate account liabilities				0
Liabilities related to discontinued operations				0
Total liabilities				(5,685)
Commitments and contingencies
Equity:
Class A common stock				0
Additional paid-in capital				0
Accumulated other comprehensive income (loss)				5,606
Retained earnings				0
Treasury stock, at cost				0
Total Genworth Financial, Inc.'s stockholders' equity				5,606
Noncontrolling interests				0
Total equity				5,606
Total liabilities and equity				(79)
Cumulative effect of change in accounting | Changes in measurement of assets and liabilities | Accounting Standards Update 2018-12
Assets
Total investments				0
Cash, cash equivalents and restricted cash				0
Accrued investment income				0
Deferred acquisition costs				0
Intangible assets				0
Reinsurance recoverable				1,214
Less: Allowance for credit losses				0
Reinsurance recoverable, net				1,214
Other assets				(89)
Deferred tax asset				497
Market risk benefit assets				0
Separate account assets				0
Assets related to discontinued operations				0
Total assets				1,622
Liabilities:
Future policy benefits				14,654
Policyholder account balances				0
Market risk benefit liabilities				0
Liability for policy and contract claims				(10,725)
Unearned premiums				(468)
Other liabilities				0
Long-term borrowings				0
Separate account liabilities				0
Liabilities related to discontinued operations				0
Total liabilities				3,461
Commitments and contingencies
Equity:
Class A common stock				0
Additional paid-in capital				0
Accumulated other comprehensive income (loss)				0
Retained earnings				(1,839)
Treasury stock, at cost				0
Total Genworth Financial, Inc.'s stockholders' equity				(1,839)
Noncontrolling interests				0
Total equity				(1,839)
Total liabilities and equity				1,622
Cumulative effect of change in accounting | Change in discount rate | Accounting Standards Update 2018-12
Assets
Total investments				0
Cash, cash equivalents and restricted cash				0
Accrued investment income				0
Deferred acquisition costs				0
Intangible assets				0
Reinsurance recoverable				10,149
Less: Allowance for credit losses				0
Reinsurance recoverable, net				10,149
Other assets				0
Deferred tax asset				4,624
Market risk benefit assets				0
Separate account assets				0
Assets related to discontinued operations				0
Total assets				14,773
Liabilities:
Future policy benefits				31,893
Policyholder account balances				0
Market risk benefit liabilities				0
Liability for policy and contract claims				0
Unearned premiums				0
Other liabilities				0
Long-term borrowings				0
Separate account liabilities				0
Liabilities related to discontinued operations				0
Total liabilities				31,893
Commitments and contingencies
Equity:
Class A common stock				0
Additional paid-in capital				0
Accumulated other comprehensive income (loss)				(17,120)
Retained earnings				0
Treasury stock, at cost				0
Total Genworth Financial, Inc.'s stockholders' equity				(17,120)
Noncontrolling interests				0
Total equity				(17,120)
Total liabilities and equity				14,773
Cumulative effect of change in accounting | Recognize MRBs | Accounting Standards Update 2018-12
Assets
Total investments				0
Cash, cash equivalents and restricted cash				0
Accrued investment income				0
Deferred acquisition costs				0
Intangible assets				0
Reinsurance recoverable				(92)
Less: Allowance for credit losses				0
Reinsurance recoverable, net				(92)
Other assets				248
Deferred tax asset				105
Market risk benefit assets				22
Separate account assets				0
Assets related to discontinued operations				0
Total assets				283
Liabilities:
Future policy benefits				0
Policyholder account balances				(641)
Market risk benefit liabilities				1,310
Liability for policy and contract claims				0
Unearned premiums				0
Other liabilities				4
Long-term borrowings				0
Separate account liabilities				0
Liabilities related to discontinued operations				0
Total liabilities				673
Commitments and contingencies
Equity:
Class A common stock				0
Additional paid-in capital				0
Accumulated other comprehensive income (loss)				(19)
Retained earnings				(371)
Treasury stock, at cost				0
Total Genworth Financial, Inc.'s stockholders' equity				(390)
Noncontrolling interests				0
Total equity				(390)
Total liabilities and equity				$ 283
Previously reported
Assets
Total investments					74,701
Cash, cash equivalents and restricted cash					2,561
Accrued investment income					655
Deferred acquisition costs		2,200			1,487
Intangible assets		241			157
Reinsurance recoverable		16,495			16,864
Less: Allowance for credit losses		(60)			(45)
Reinsurance recoverable, net		16,435			16,819
Other assets		415			404
Deferred tax asset		1,344			65
Market risk benefit assets		0			0
Separate account assets					6,081
Assets related to discontinued operations					2,817
Total assets		86,442			105,747
Liabilities:
Future policy benefits		38,064			42,695
Policyholder account balances		17,113			21,503
Market risk benefit liabilities		0			0
Liability for policy and contract claims		12,234			11,486
Unearned premiums		584			775
Other liabilities		1,672			1,614
Long-term borrowings					3,403
Separate account liabilities					6,081
Liabilities related to discontinued operations					2,370
Total liabilities		75,703			89,927
Commitments and contingencies
Equity:
Class A common stock					1
Additional paid-in capital					12,008
Accumulated other comprehensive income (loss)		(2,220)			4,425
Retained earnings		3,098			1,584
Treasury stock, at cost					(2,700)
Total Genworth Financial, Inc.'s stockholders' equity		9,984			15,318
Noncontrolling interests					502
Total equity		10,739			15,820
Total liabilities and equity		$ 86,442			$ 105,747