Earnings (Loss) Per Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended																12 Months Ended
	Dec. 31, 2015		Sep. 30, 2015		Jun. 30, 2015		Mar. 31, 2015		Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Earnings (Loss) Per Share [Abstract]
Weighted-average common shares used in basic earnings (loss) per common share calculations	497.6		497.4		497.4		497.0		496.7		496.6		496.6		495.8		497.4		496.4		493.6
Stock options, restricted stock units and stock appreciation rights																	0.0		0.0		5.1
Weighted-average common shares used in diluted earnings (loss) per common share calculations	497.6	[1]	497.4	[1]	499.3	[1]	498.9	[1]	496.7	[2]	496.6	[2]	503.6	[2]	502.7	[2]	497.4	[3]	496.4	[3]	498.7	[3]
Income (loss) from continuing operations:
Income (loss) from continuing operations	$ (167)	[4]	$ (217)	[4]	$ 175	[4]	$ 203	[4]	$ (846)	[5]	$ (793)	[5]	$ 224	[5]	$ 210	[5]	$ (6)		$ (1,205)		$ 680
Less: income from continuing operations attributable to noncontrolling interests																	202		196		154
Income (loss) from continuing operations available to Genworth Financial, Inc.'s common stockholders																	$ (208)		$ (1,401)		$ 526
Basic per common share	$ (0.44)		$ (0.53)		$ 0.24		$ 0.31		$ (1.81)		$ (1.71)		$ 0.35		$ 0.35		$ (0.42)		$ (2.82)		$ 1.07
Diluted per common share	$ (0.44)		$ (0.53)		$ 0.24		$ 0.31		$ (1.81)		$ (1.71)		$ 0.34		$ 0.35		$ (0.42)		$ (2.82)		$ 1.05
Income (loss) from discontinued operations:
Income (loss) from discontinued operations, net of taxes	$ (73)	[6]	$ (21)	[6]	$ (314)	[6]	$ 1	[6]	$ 138		$ 6		$ 4		$ 9		$ (407)		$ 157		$ 34
Less: income from discontinued operations, net of taxes, attributable to noncontrolling interests																	0		0		0
Income (loss) from discontinued operations, net of taxes, available to Genworth Financial, Inc.'s common stockholders																	$ (407)		$ 157		$ 34
Basic per common share																	$ (0.82)		$ 0.32		$ 0.07
Diluted per common share																	$ (0.82)		$ 0.32		$ 0.07
Net income (loss):
Income (loss) from continuing operations	(167)	[4]	(217)	[4]	175	[4]	203	[4]	(846)	[5]	(793)	[5]	224	[5]	210	[5]	$ (6)		$ (1,205)		$ 680
Income (loss) from discontinued operations, net of taxes	(73)	[6]	(21)	[6]	(314)	[6]	1	[6]	138		6		4		9		(407)		157		34
Net income (loss)	(240)	[4],[6]	(238)	[4],[6]	(139)	[4],[6]	204	[4],[6]	(708)	[5]	(787)	[5]	228	[5]	219	[5]	(413)		(1,048)		714
Less: net income attributable to noncontrolling interests	52		46		54		50		52		57		52		35		202		196		154
Net income (loss) available to Genworth Financial, Inc.'s common stockholders	$ (292)		$ (284)		$ (193)		$ 154		$ (760)	[5]	$ (844)	[5]	$ 176	[5]	$ 184	[5]	$ (615)		$ (1,244)		$ 560
Basic per common share	$ (0.59)		$ (0.57)		$ (0.39)		$ 0.31		$ (1.53)		$ (1.70)		$ 0.35		$ 0.37		$ (1.24)		$ (2.51)		$ 1.13
Diluted per common share	$ (0.59)		$ (0.57)		$ (0.39)		$ 0.31		$ (1.53)		$ (1.70)		$ 0.35		$ 0.37		$ (1.24)		$ (2.51)		$ 1.12

[1] Under applicable accounting guidance, companies in a loss position are required to use basic weighted-average common shares outstanding in the calculation of diluted loss per share. Therefore, as a result of our loss from continuing operations available to Genworth Financial, Inc.'s common stockholders and net loss available to Genworth Financial, Inc.'s common stockholders for the three months ended September 30, 2015 and December 31, 2015, we were required to use basic weighted-average common shares outstanding in the calculation of diluted loss per share for the three months ended September 30, 2015 and December 31, 2015, as the inclusion of shares for stock options, RSUs and SARs of 1.3 million and 1.4 million, respectively, would have been antidilutive to the calculation. If we had not incurred a loss from continuing operations available to Genworth Financial, Inc.'s common stockholders and net loss available to Genworth Financial, Inc.'s common stockholders for the three months ended September 30, 2015 and December 31, 2015, dilutive potential weighted-average common shares outstanding would have been 498.7 and 499.0 million, respectively.

[2] Under applicable accounting guidance, companies in a loss position are required to use basic weighted-average common shares outstanding in the calculation of diluted loss per share. Therefore, as a result of our loss from continuing operations available to Genworth Financial, Inc.'s common stockholders and net loss available to Genworth Financial, Inc.'s common stockholders for the three months ended September 30, 2014 and December 31, 2014, we were required to use basic weighted-average common shares outstanding in the calculation of diluted loss per share for the three months ended September 30, 2014 and December 31, 2014, as the inclusion of shares for stock options, RSUs and SARs of 5.4 million and 3.2 million, respectively, would have been antidilutive to the calculation. If we had not incurred a loss from continuing operations available to Genworth Financial, Inc.'s common stockholders and net loss available to Genworth Financial, Inc.'s common stockholders for the three months ended September 30, 2014 and December 31, 2014, dilutive potential weighted-average common shares outstanding would have been 502.0 million and 499.9 million, respectively.

[3] Under applicable accounting guidance, companies in a loss position are required to use basic weighted-average common shares outstanding in the calculation of diluted loss per share. Therefore, as a result of our loss from continuing operations available to Genworth Financial, Inc.'s common stockholders and net loss available to Genworth Financial, Inc.'s common stockholders for the years ended December 31, 2015 and 2014, we were required to use basic weighted-average common shares outstanding in the calculation of diluted loss per share for the years ended December 31, 2015 and 2014, as the inclusion of shares for stock options, restricted stock units ("RSUs") and stock appreciation rights ("SARs") of 1.6 million and 5.6 million, respectively, would have been antidilutive to the calculation. If we had not incurred a loss from continuing operations available to Genworth Financial, Inc.'s common stockholders and net loss available to Genworth Financial, Inc.'s common stockholders for the years ended December 31, 2015 and 2014, dilutive potential weighted-average common shares outstanding would have been 499.0 million and 502.0 million, respectively.

[4] We completed our annual review of assumptions in the fourth quarter of 2015, which primarily resulted in $194 million, net of taxes, of charges, which included $36 million, net of taxes, of corrections related to reinsurance inputs, in our universal and term universal life insurance products. We also recorded an expected loss of $134 million, net of taxes, related to the planned sale of our mortgage insurance business in Europe in the fourth quarter of 2015.

[5] During the fourth quarter of 2014, we completed our annual loss recognition testing of our long-term care insurance business which resulted in additional charges of $478 million, net of taxes. During the fourth quarter of 2014, we also recorded goodwill impairments of $274 million, net of taxes, in our U.S. Life Insurance segment. There was $205 million net tax impact in the fourth quarter of 2014 from potential business portfolio changes. We recognized a tax charge of $174 million in the fourth quarter of 2014 associated with our Australian mortgage insurance business as we can no longer assert our intent to permanently reinvest earnings in that business. In addition, in connection with our plans to sell our lifestyle protection insurance business, we made a change to the permanent reinvestment assertion of one of its legal entities recognizing tax expense of $31 million in the fourth quarter of 2014. We recorded a correction of $32 million, net of taxes, in our life insurance business related to reserves on a reinsurance transaction in the fourth quarter of 2014. Our long-term care insurance claim reserves also increased in the fourth quarter of 2014 as a result of a $44 million unfavorable correction related to claims in course of settlement arising in connection with the implementation of our updated assumptions and methodologies as part of our comprehensive claims review completed in the third quarter of 2014, partially offset by a $28 million favorable refinement of assumptions for claim termination rates.

[6] We completed the sale of our lifestyle protection insurance business on December 1, 2015 and recorded an additional loss of $63 million, net of taxes, in the fourth quarter of 2015. The additional loss in the fourth quarter of 2015 was primarily related to the write off of currency translation adjustments on a holding company that was not part of the sale but related to our lifestyle protection insurance business that was substantially liquidated after the completion of the sale.