Borrowings and Other Financings - Long Term Borrowings (Parenthetical) (Detail)	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2016	Dec. 31, 2015	Jan. 31, 2016
Genworth Financial Mortgage Insurance Pty Limited
Debt Instrument [Line Items]
Debt instrument, maturity year		2025
8.625% Senior Notes, Due 2016 | Genworth Holdings
Debt Instrument [Line Items]
Interest rate		8.625%	8.625%	8.625%
Debt instrument, maturity year		2016	2016
6.52% Senior Notes, Due 2018 | Genworth Holdings
Debt Instrument [Line Items]
Interest rate		6.52%	6.52%
Debt instrument, maturity year		2018	2018
7.70% Senior Notes, Due 2020 | Genworth Holdings
Debt Instrument [Line Items]
Interest rate		7.70%	7.70%
Debt instrument, maturity year		2020	2020
7.20% Senior Notes, Due 2021 | Genworth Holdings
Debt Instrument [Line Items]
Interest rate		7.20%	7.20%
Debt instrument, maturity year		2021	2021
7.625% Senior Notes, Due 2021 | Genworth Holdings
Debt Instrument [Line Items]
Interest rate		7.625%	7.625%
Debt instrument, maturity year		2021	2021
4.90% Senior Notes, Due 2023 | Genworth Holdings
Debt Instrument [Line Items]
Interest rate		4.90%	4.90%
Debt instrument, maturity year		2023	2023
4.80% Senior Notes, Due 2024 | Genworth Holdings
Debt Instrument [Line Items]
Interest rate		4.80%	4.80%
Debt instrument, maturity year		2024	2024
6.50% Senior Notes, Due 2034 | Genworth Holdings
Debt Instrument [Line Items]
Interest rate		6.50%	6.50%
Debt instrument, maturity year		2034	2034
6.15% Fixed-to-Floating Rate Junior Subordinated Notes, Due 2066 | Genworth Holdings
Debt Instrument [Line Items]
Interest rate		6.15%	6.15%
Debt instrument, maturity year		2066	2066
5.68% Senior Notes, Due 2020 | Genworth MI Canada Inc.
Debt Instrument [Line Items]
Interest rate		5.68%	5.68%
Debt instrument, maturity year		2020	2020
4.24% Senior Notes, due 2024 | Genworth MI Canada Inc.
Debt Instrument [Line Items]
Interest rate		4.24%	4.24%
Debt instrument, maturity year		2024	2024
Floating Rate Junior Notes, Due 2021 | Genworth Financial Mortgage Insurance Pty Limited
Debt Instrument [Line Items]
Debt instrument, maturity year	2021	2021	2021
Floating Rate Junior Notes, Due 2025 | Genworth Financial Mortgage Insurance Pty Limited
Debt Instrument [Line Items]
Debt instrument, maturity year		2025	2025