Schedule III Genworth Financial, Inc. Supplemental Insurance Information (Schedule of Supplemental Insurance Information) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Supplementary Insurance Information, by Segment [Line Items]
Deferred Acquisition Costs	$ 3,571	$ 4,398
Future Policy Benefits	37,063	36,475
Policyholder Account Balances	25,662	26,209
Liability for Policy and Contract Claims	9,256	8,095
Unearned Premiums	3,378	3,308
Premium Revenue	4,160	4,579	$ 4,700
Net Investment Income	3,159	3,138	3,142
Interest Credited and Benefits and Other Changes in Policy Reserves	5,941	5,869	7,155
Amortization of Deferred Acquisition Costs	481	902	383
Other Operating Expenses	1,627	1,792	2,490
Premiums Written	4,208	4,794	4,913
U.S. Mortgage Insurance
Supplementary Insurance Information, by Segment [Line Items]
Deferred Acquisition Costs	28	22
Future Policy Benefits	0	0
Policyholder Account Balances	0	0
Liability for Policy and Contract Claims	635	849
Unearned Premiums	342	258
Premium Revenue	660	602	578
Net Investment Income	63	58	59
Interest Credited and Benefits and Other Changes in Policy Reserves	160	222	357
Amortization of Deferred Acquisition Costs	9	7	5
Other Operating Expenses	170	158	142
Premiums Written	744	682	628
Canada Mortgage Insurance
Supplementary Insurance Information, by Segment [Line Items]
Deferred Acquisition Costs	121	108
Future Policy Benefits	0	0
Policyholder Account Balances	0	0
Liability for Policy and Contract Claims	112	87
Unearned Premiums	1,595	1,460
Premium Revenue	481	466	515
Net Investment Income	126	130	155
Interest Credited and Benefits and Other Changes in Policy Reserves	104	96	102
Amortization of Deferred Acquisition Costs	37	35	35
Other Operating Expenses	97	85	114
Premiums Written	576	641	583
Australia Mortgage Insurance
Supplementary Insurance Information, by Segment [Line Items]
Deferred Acquisition Costs	31	35
Future Policy Benefits	0	0
Policyholder Account Balances	0	0
Liability for Policy and Contract Claims	211	165
Unearned Premiums	850	963
Premium Revenue	337	357	406
Net Investment Income	94	114	144
Interest Credited and Benefits and Other Changes in Policy Reserves	113	81	78
Amortization of Deferred Acquisition Costs	13	16	15
Other Operating Expenses	107	110	113
Premiums Written	231	328	509
U.S. Life Insurance
Supplementary Insurance Information, by Segment [Line Items]
Deferred Acquisition Costs	3,149	3,963
Future Policy Benefits	37,060	36,471
Policyholder Account Balances	22,285	23,009
Liability for Policy and Contract Claims	8,276	6,969
Unearned Premiums	586	621
Premium Revenue	2,670	3,128	3,169
Net Investment Income	2,726	2,701	2,665
Interest Credited and Benefits and Other Changes in Policy Reserves	5,387	5,288	6,438
Amortization of Deferred Acquisition Costs	394	816	291
Other Operating Expenses	695	832	1,648
Premiums Written	2,644	3,115	3,172
Runoff
Supplementary Insurance Information, by Segment [Line Items]
Deferred Acquisition Costs	242	270
Future Policy Benefits	3	4
Policyholder Account Balances	3,377	3,200
Liability for Policy and Contract Claims	15	18
Unearned Premiums	5	6
Premium Revenue	0	1	3
Net Investment Income	147	138	129
Interest Credited and Benefits and Other Changes in Policy Reserves	173	168	156
Amortization of Deferred Acquisition Costs	28	28	37
Other Operating Expenses	70	78	87
Premiums Written	0	1	2
Corporate and Other
Supplementary Insurance Information, by Segment [Line Items]
Deferred Acquisition Costs	0	0
Future Policy Benefits	0	0
Policyholder Account Balances	0	0
Liability for Policy and Contract Claims	7	7
Unearned Premiums	0	0
Premium Revenue	12	25	29
Net Investment Income	3	(3)	(10)
Interest Credited and Benefits and Other Changes in Policy Reserves	4	14	24
Amortization of Deferred Acquisition Costs	0	0	0
Other Operating Expenses	488	529	386
Premiums Written	$ 13	$ 27	$ 19