Noncontrolling Interests - Additional Information (Detail) $ / shares in Units, shares in Millions, $ in Millions, $ in Millions				1 Months Ended	12 Months Ended
	Feb. 28, 2018 AUD ($) shares	Feb. 28, 2018 USD ($) shares	May 11, 2015 shares	Nov. 30, 2019 AUD ($) $ / shares	Dec. 31, 2019 AUD ($) shares	Dec. 31, 2019 USD ($) shares	Dec. 31, 2018 AUD ($) shares	Dec. 31, 2018 USD ($) shares	Dec. 31, 2017 AUD ($) shares	Dec. 31, 2017 USD ($) shares	Dec. 12, 2019 USD ($)	Sep. 30, 2019 AUD ($) $ / shares	Feb. 28, 2019 AUD ($)	May 31, 2018 AUD ($)	Aug. 31, 2017 AUD ($)	May 15, 2015	May 14, 2014
Noncontrolling Interest [Line Items]
Dividend paid to noncontrolling interests						$ 87		$ 40		$ 53
Stockholders' Equity Attributable to Noncontrolling Interest						$ 447		$ 1,739
Genworth MI Canada Inc.
Noncontrolling Interest [Line Items]
Beneficial ownership percentage of ordinary shares											57.00%
Stockholders' Equity Attributable to Noncontrolling Interest											$ 1,300
Genworth Australia
Noncontrolling Interest [Line Items]
Beneficial ownership percentage of ordinary shares						52.00%							52.00%			52.00%
Repurchase of subsidiary shares through issuer bid, number of shares | shares	19.0	19.0			25.0	25.0	36.0	36.0	17.0	17.0
Common shares repurchased, value	$ 49				$ 64		$ 100		$ 51
Amount received as a result of participation in Issuer Bid		$ 20				$ 23		$ 37		$ 20
Dividend paid to noncontrolling interests						$ 87		$ 40		$ 53
Shares sold | shares			92.3
Maximum aggregate amount of share buy-back program													$ 100	$ 100	$ 100
Special dividends paid by subsidiary per share | $ / shares				$ 0.242								$ 0.219
Remaining amount of share buy-back program												$ 36
Aggregate Distribution				$ 100
Genworth Australia | IPO
Noncontrolling Interest [Line Items]
Beneficial ownership percentage of ordinary shares																	66.20%