Earning (Loss) Per Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share [Abstract]
Weighted-average shares used in basic earnings per share calculations		503.5	500.7	502.7	500.3
Stock options, restricted stock units and stock appreciation rights		7.7	2.6	6.8	2.6
Weighted-average shares used in diluted earnings per share calculations		511.2	503.3	509.5	502.9
Income from continuing operations:
Income from continuing operations		$ 138	$ 105	$ 464	$ 340
Less: net income from continuing operations attributable to noncontrolling interests		10	18	45	62
Income from continuing operations available to Genworth Financial, Inc.'s common stockholders		$ 128	$ 87	$ 419	$ 278
Basic per share		$ 0.25	$ 0.17	$ 0.83	$ 0.56
Diluted per share		$ 0.25	$ 0.17	$ 0.82	$ 0.55
Income (loss) from discontinued operations:
Income (loss) from discontinued operations, net of taxes		$ (80)	$ 105	$ 42	$ 284
Less: net income from discontinued operations, net of taxes, attributable to noncontrolling interests		30	46	101	114
Income (loss) from discontinued operations available to Genworth Financial, Inc.'s common stockholders		$ (110)	$ 59	$ (59)	$ 170
Basic per share		$ (0.22)	$ 0.12	$ (0.12)	$ 0.34
Diluted per share		$ (0.21)	$ 0.12	$ (0.12)	$ 0.34
Net income:
Income from continuing operations		$ 138	$ 105	$ 464	$ 340
Income (loss) from discontinued operations, net of taxes		(80)	105	42	284
Net income		58	210	506	624
Less: net income attributable to noncontrolling interests		40	64	146	176
Net income available to Genworth Financial, Inc.'s common stockholders		$ 18	$ 146	$ 360	$ 448
Basic per share	[1]	$ 0.04	$ 0.29	$ 0.72	$ 0.89
Diluted per share	[1]	$ 0.04	$ 0.29	$ 0.71	$ 0.89

[1] May not total due to whole number calculation.