Summary of Net Operating Income (Loss) for Segments and Corporate and Other Activities (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Segment Reporting Information [Line Items]
Net income (loss) available to Genworth Financial, Inc.'s common stockholders	$ 181	$ 240	$ 330	$ 427
Add: net income from continuing operations attributable to noncontrolling interests	38	0	68	0
Add: net income from discontinued operations attributable to noncontrolling interests	0	0	0	8
Net income	219	240	398	435
Less: income (loss) from discontinued operations, net of taxes	(1)	(5)	(3)	16
Income from continuing operations	220	245	401	419
Less: net income from continuing operations attributable to noncontrolling interests	38	0	68	0
Income from continuing operations available to Genworth Financial, Inc.'s common stockholders	182	245	333	419
Net investment (gains) losses, net	(10)	(70)	(38)	(103)
(Gains) losses on early extinguishment of debt	1	0	4	4
Expenses related to restructuring	1	5	1	26
Taxes on adjustments	2	14	7	16
Adjusted operating income available to Genworth Financial, Inc.'s common stockholders	176	194	307	362
Segment, Continuing Operations | Enact
Segment Reporting Information [Line Items]
Adjusted operating income available to Genworth Financial, Inc.'s common stockholders	167	135	302	261
Segment, Continuing Operations | Long-term Care Insurance
Segment Reporting Information [Line Items]
Adjusted operating income available to Genworth Financial, Inc.'s common stockholders	34	98	93	193
Segment, Continuing Operations | Life Insurance
Segment Reporting Information [Line Items]
Adjusted operating income available to Genworth Financial, Inc.'s common stockholders	(34)	(40)	(113)	(103)
Segment, Continuing Operations | Fixed Annuities
Segment Reporting Information [Line Items]
Adjusted operating income available to Genworth Financial, Inc.'s common stockholders	21	13	37	43
Segment, Continuing Operations | U.S. Life Insurance
Segment Reporting Information [Line Items]
Adjusted operating income available to Genworth Financial, Inc.'s common stockholders	21	71	17	133
Segment, Continuing Operations | Runoff
Segment Reporting Information [Line Items]
Adjusted operating income available to Genworth Financial, Inc.'s common stockholders	2	15	11	27
Segment, Continuing Operations | Corporate and Other
Segment Reporting Information [Line Items]
Adjusted operating income available to Genworth Financial, Inc.'s common stockholders	$ (14)	$ (27)	$ (23)	$ (59)