Summary of Net Operating Income (Loss) for Segments and Corporate and Other Activities (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Segment Reporting Information [Line Items]
Net income available to Genworth Financial, Inc.'s common stockholders	$ 104	$ 314	$ 434	$ 741
Add: net income from continuing operations attributable to noncontrolling interests	35	4	103	4
Add: net income from discontinued operations attributable to noncontrolling interests	0	0	0	8
Net income	139	318	537	753
Less: income from discontinued operations, net of taxes	5	12	2	28
Income from continuing operations	134	306	535	725
Less: net income from continuing operations attributable to noncontrolling interests	35	4	103	4
Income from continuing operations available to Genworth Financial, Inc.'s common stockholders	99	302	432	721
Net investment (gains) losses, net	67	(88)	29	(191)
(Gains) losses on early extinguishment of debt	3	6	7	10
Expenses related to restructuring	0	3	1	29
Pension plan termination costs	6	0	6	0
Taxes on adjustments	(16)	16	(9)	32
Adjusted operating income available to Genworth Financial, Inc.'s common stockholders	159	239	466	601
Segment, Continuing Operations | Enact
Segment Reporting Information [Line Items]
Adjusted operating income available to Genworth Financial, Inc.'s common stockholders	156	134	458	395
Segment, Continuing Operations | Long-term Care Insurance
Segment Reporting Information [Line Items]
Adjusted operating income available to Genworth Financial, Inc.'s common stockholders	25	133	118	326
Segment, Continuing Operations | Life Insurance
Segment Reporting Information [Line Items]
Adjusted operating income available to Genworth Financial, Inc.'s common stockholders	(33)	(68)	(146)	(171)
Segment, Continuing Operations | Fixed Annuities
Segment Reporting Information [Line Items]
Adjusted operating income available to Genworth Financial, Inc.'s common stockholders	19	28	56	71
Segment, Continuing Operations | U.S. Life Insurance
Segment Reporting Information [Line Items]
Adjusted operating income available to Genworth Financial, Inc.'s common stockholders	11	93	28	226
Segment, Continuing Operations | Runoff
Segment Reporting Information [Line Items]
Adjusted operating income available to Genworth Financial, Inc.'s common stockholders	9	11	20	38
Segment, Continuing Operations | Corporate and Other
Segment Reporting Information [Line Items]
Adjusted operating income available to Genworth Financial, Inc.'s common stockholders	$ (17)	$ 1	$ (40)	$ (58)