Accounting Changes - Summary Of Impact Of Accounting Changes Due To Recogntion And Measurement Of Long Duration Insurance Contracts On The Statement Of Financial Position (Detail) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021	Jan. 01, 2021	Dec. 31, 2020
Assets
Total investments	$ 59,842	$ 58,948			$ 74,701
Cash, cash equivalents and restricted cash	1,752	1,799	$ 1,291		2,561
Accrued investment income	700	643			655
Deferred acquisition costs	2,150	2,211		$ 2,488	2,809
Intangible assets	203	203			271
Reinsurance recoverable	19,606	19,059			28,135
Less: Allowance for credit losses	(64)	(63)			(45)
Reinsurance recoverable, net	19,542	18,996			28,090
Other assets	478	488			563
Deferred tax asset	2,004	1,968			3,765
Market risk benefit assets	28	26			22
Separate account assets	4,479	4,417			6,081
Total assets	91,178	89,699			122,335
Liabilities and equity
Future policy benefits	57,558	55,349			84,736
Policyholder account balances	16,202	16,564			19,633
Market risk benefit liabilities	761	748			1,310
Liability for policy and contract claims	665	683	809	819	761
Unearned premiums	189	203			307
Other liabilities	1,492	1,675			1,618
Long-term borrowings	1,600	1,611			3,403
Separate account liabilities	4,479	4,417			6,081
Liabilities related to discontinued operations	7	8			2,370
Total liabilities	82,953	81,258			120,219
Commitments and Contingencies
Equity:
Class A common stock	1	1			1
Additional paid-in capital	11,863	11,869			12,008
Accumulated other comprehensive income (loss)	(2,858)	(2,617)	(4,564)	(5,881)	(7,126)
Retained earnings	1,259	1,197			(569)
Treasury stock, at cost	(2,833)	(2,764)			(2,700)
Total Genworth Financial, Inc.'s stockholders' equity	7,432	7,686			1,614
Noncontrolling interests	793	755			502
Total equity	8,225	8,441	$ 5,729	$ 4,233	2,116
Total liabilities and equity	$ 91,178	89,699			$ 122,335
Previously reported
Assets
Total investments		58,948				$ 74,701
Cash, cash equivalents and restricted cash		1,799				2,561
Accrued investment income		643				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		4,417				6,081
Total assets		86,442				105,747
Liabilities and equity
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		1,611				3,403
Separate account liabilities		4,417				6,081
Liabilities related to discontinued operations		8				2,370
Total liabilities		75,703				89,927
Commitments and Contingencies
Equity:
Class A common stock		1				1
Additional paid-in capital		11,869				12,008
Accumulated other comprehensive income (loss)		(2,220)				4,425
Retained earnings		3,098				1,584
Treasury stock, at cost		(2,764)				(2,700)
Total Genworth Financial, Inc.'s stockholders' equity		9,984				15,318
Noncontrolling interests		755				502
Total equity		10,739				15,820
Total liabilities and equity		86,442				$ 105,747
Revision of prior periods | 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		(40)
Intangible assets		(8)
Reinsurance recoverable		0
Less: Allowance for credit losses		0
Reinsurance recoverable, net		0
Other assets		0
Deferred tax asset		(5)
Market risk benefit assets		0
Separate account assets		0
Total assets		(53)
Liabilities and equity
Future policy benefits		(5)
Policyholder account balances		(67)
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		(72)
Commitments and Contingencies
Equity:
Class A common stock		0
Additional paid-in capital		0
Accumulated other comprehensive income (loss)		19
Retained earnings		0
Treasury stock, at cost		0
Total Genworth Financial, Inc.'s stockholders' equity		19
Noncontrolling interests		0
Total equity		19
Total liabilities and equity		(53)
Revision of prior periods | 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		51
Intangible assets		(30)
Reinsurance recoverable		1,180
Less: Allowance for credit losses		(3)
Reinsurance recoverable, net		1,177
Other assets		(89)
Deferred tax asset		488
Market risk benefit assets		0
Separate account assets		0
Total assets		1,597
Liabilities and equity
Future policy benefits		15,303
Policyholder account balances		20
Market risk benefit liabilities		0
Liability for policy and contract claims		(11,551)
Unearned premiums		(381)
Other liabilities		0
Long-term borrowings		0
Separate account liabilities		0
Liabilities related to discontinued operations		0
Total liabilities		3,391
Commitments and Contingencies
Equity:
Class A common stock		0
Additional paid-in capital		0
Accumulated other comprehensive income (loss)		0
Retained earnings		(1,794)
Treasury stock, at cost		0
Total Genworth Financial, Inc.'s stockholders' equity		(1,794)
Noncontrolling interests		0
Total equity		(1,794)
Total liabilities and equity		1,597
Revision of prior periods | 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		1,470
Less: Allowance for credit losses		0
Reinsurance recoverable, net		1,470
Other assets		0
Deferred tax asset		110
Market risk benefit assets		0
Separate account assets		0
Total assets		1,580
Liabilities and equity
Future policy benefits		1,987
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		1,987
Commitments and Contingencies
Equity:
Class A common stock		0
Additional paid-in capital		0
Accumulated other comprehensive income (loss)		(407)
Retained earnings		0
Treasury stock, at cost		0
Total Genworth Financial, Inc.'s stockholders' equity		(407)
Noncontrolling interests		0
Total equity		(407)
Total liabilities and equity		1,580
Revision of prior periods | Recognize market risk benefits | 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		(86)
Less: Allowance for credit losses		0
Reinsurance recoverable, net		(86)
Other assets		162
Deferred tax asset		31
Market risk benefit assets		26
Separate account assets		0
Total assets		133
Liabilities and equity
Future policy benefits		0
Policyholder account balances		(502)
Market risk benefit liabilities		748
Liability for policy and contract claims		0
Unearned premiums		0
Other liabilities		3
Long-term borrowings		0
Separate account liabilities		0
Liabilities related to discontinued operations		0
Total liabilities		249
Commitments and Contingencies
Equity:
Class A common stock		0
Additional paid-in capital		0
Accumulated other comprehensive income (loss)		(9)
Retained earnings		(107)
Treasury stock, at cost		0
Total Genworth Financial, Inc.'s stockholders' equity		(116)
Noncontrolling interests		0
Total equity		(116)
Total liabilities and equity		$ 133