Schedule II Genworth Financial, Inc. (Parent Company Only) (Statements of Cash Flows) (Detail) - USD ($) $ in Millions	3 Months Ended																12 Months Ended
	Dec. 31, 2017		Sep. 30, 2017		Jun. 30, 2017		Mar. 31, 2017		Dec. 31, 2016		Sep. 30, 2016		Jun. 30, 2016		Mar. 31, 2016		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows used by operating activities:
Net income (loss) available to Genworth Financial, Inc.'s common stockholders	$ 265	[1]	$ 175	[1]	$ 271	[1]	$ 216	[1]	$ (63)	[2]	$ (332)	[2]	$ 220	[2]	$ 108	[2]	$ 927	$ (67)	$ (413)
Less loss from discontinued operations, net of taxes	0		$ 9		$ 0		0		4		$ (15)		$ 21		19		9	29	407
Adjustments to reconcile net income (loss) to net cash from (used by) operating activities:
Equity in (income) loss from subsidiaries																	0	0	0
Deferred income taxes																	(368)	145	(196)
Stock-based compensation expense																	42	32	16
Change in certain assets and liabilities:
Accrued investment income and other assets																	30	(358)	(106)
Current tax liabilities																	(4)	32	(15)
Other liabilities and other policy-related balances																	368	685	293
Net cash from operating activities																	2,554	1,852	1,591
Cash flows from (used by) investing activities:
Intercompany notes receivable																	0	0	0
Capital contributions paid to subsidiaries																	0		0
Net cash from (used by) investing activities																	(759)	(2,120)	(404)
Cash flows from (used by) financing activities:
Other, net																	(54)	(44)	(98)
Intercompany notes payable																	0	0	0
Net cash from (used by) financing activities																	(1,768)	(2,931)	(42)
Effect of exchange rate changes on cash and cash equivalents																	64	(10)	(70)
Cash and cash equivalents at beginning of year							2,784								5,965		2,784	5,965
Cash and cash equivalents at end of year	2,875								2,784								2,875	2,784	5,965
Parent Company
Cash flows used by operating activities:
Net income (loss) available to Genworth Financial, Inc.'s common stockholders																	817	(277)	(615)
Less loss from discontinued operations, net of taxes																	0	1	9
Adjustments to reconcile net income (loss) to net cash from (used by) operating activities:
Equity in (income) loss from subsidiaries																	(878)	166	579
Deferred income taxes																	10	(6)	(4)
Stock-based compensation expense																	30	23	21
Change in certain assets and liabilities:
Accrued investment income and other assets																	5	(9)	3
Current tax liabilities																	23	0	(3)
Other liabilities and other policy-related balances																	(35)	20	2
Net cash from operating activities																	(28)	(82)	(8)
Cash flows from (used by) investing activities:
Intercompany notes receivable																	0	0	9
Capital contributions paid to subsidiaries																	(12)	0	0
Payments for business purchased																	(7)	0	0
Net cash from (used by) investing activities																	(19)	0	9
Cash flows from (used by) financing activities:
Other, net																	(1)	0	(3)
Intercompany notes payable																	48	82	2
Net cash from (used by) financing activities																	47	82	(1)
Effect of exchange rate changes on cash and cash equivalents																	0	0	0
Cash and cash equivalents at beginning of year							$ 0								$ 0		0	0	0
Cash and cash equivalents at end of year	$ 0								$ 0								$ 0	$ 0	$ 0

[1] In the fourth quarter of 2017, we recorded $456 million of net tax benefits primarily from changes in U.S. tax legislation under the TCJA and other items. These tax benefits were mostly related to a $258 million release of a valuation allowance recorded in 2016, the impact from changes in the federal tax rate and the release of shareholder liability taxes, partially offset by higher transition taxes. Our valuation allowance was reduced by $258 million principally related to the TCJA and from improvements in business performance, mostly in our U.S. mortgage insurance business, as well as lower operating earnings volatility in our U.S. life insurance businesses. Our Australian mortgage insurance business completed a review of the premium earnings pattern, as described above, which resulted in an unfavorable adjustment of $152 million, net of taxes and noncontrolling interests. A portion of this loss, $11 million, was recorded in Corporate and Other activities in connection with our allocation methodology for income taxes. We also completed our annual review of assumptions in our life insurance business in the fourth quarter of 2017, as described above, which resulted in a $74 million unfavorable adjustment, net of taxes, in our universal and term universal life insurance products.

[2] Our life insurance business completed its annual review of assumptions in the fourth quarter of 2016 as described above, which resulted in $196 million, net of taxes, of charges in our universal and term universal life insurance products.