Earning (Loss) Per Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended
		Mar. 31, 2022	Mar. 31, 2021
Earnings Per Share [Abstract]
Weighted-average shares used in basic earnings per share calculations		508.3	506.0
Stock options, restricted stock units and other equity-based compensation		9.1	7.8
Weighted-average shares used in diluted earnings per share calculations		517.4	513.8
Income from continuing operations:
Income from continuing operations		$ 181	$ 174
Less: net income from continuing operations attributable to noncontrolling interests		30	0
Income from continuing operations available to Genworth Financial, Inc.'s common stockholders		$ 151	$ 174
Basic per share		$ 0.30	$ 0.35
Diluted per share		$ 0.29	$ 0.34
Income (loss) from discontinued operations:
Income (loss) from discontinued operations, net of taxes		$ (2)	$ 21
Less: net income (loss) from discontinued operations attributable to noncontrolling interests		0	8
Income (loss) from discontinued operations available to Genworth Financial, Inc.'s common stockholders		$ (2)	$ 13
Basic per share		$ 0	$ 0.02
Diluted per share		$ 0	$ 0.02
Net income:
Income from continuing operations		$ 181	$ 174
Income (loss) from discontinued operations, net of taxes		(2)	21
Net income		179	195
Less: net income attributable to noncontrolling interests		30	8
Net income available to Genworth Financial, Inc.'s common stockholders		$ 149	$ 187
Basic per share	[1]	$ 0.29	$ 0.37
Diluted per share	[1]	$ 0.29	$ 0.37

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