| Document and Entity Information | Mar. 19, 2020 |
| Document And Entity Information [Line Items] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001668428 |
| Document Type | 8-K |
| Document Period End Date | Mar. 19, 2020 |
| Entity Registrant Name | FGL HOLDINGS |
| Entity Incorporation State Country Code | E9 |
| Entity File Number | 001-37779 |
| Entity Tax Identification Number | 98-1354810 |
| Entity Address, Address Line One | 4th Floor |
| Entity Address, Address Line Two | Boundary Hall |
| Entity Address, Address Line Three | Cricket Square |
| Entity Address, City or Town | Grand Cayman |
| Entity Address, Region | Grand Cayman |
| Entity Address, Country | KY |
| Entity Address, Postal Zip Code | KY1-1102 |
| Entity Address, State or Province | KY |
| City Area Code | 1 (345) |
| Local Phone Number | 947-5614 |
| Written Communications | false |
| Soliciting Material | true |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Fair Value Measured at Net Asset Value Per Share [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Ordinary shares, par value $.0001 per share |
| Trading Symbol | FG |
| Security Exchange Name | NYSE |
| Warrant [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Warrants to purchase ordinary shares |
| Trading Symbol | FG WS |
| Security Exchange Name | NYSE |
