Schedule II - Condensed Financial Information of Parent - Guarantees (Details) - USD ($) $ in Millions	Dec. 31, 2017	Jul. 20, 2017	Dec. 31, 2016	Apr. 15, 2016	Jan. 15, 2014	Jan. 01, 2014
Guarantor Obligations [Line Items]
Revolving lines of credit, capacity	$ 6,872.0
Long-term debt	3,460.0		$ 3,550.0
Voya Holdings Debentures
Guarantor Obligations [Line Items]
Long-term debt	426.0
Unsecured and Committed
Guarantor Obligations [Line Items]
Revolving lines of credit, capacity	6,171.0
Unsecured and Committed | Voya Financial, Inc. And Security Life Of Denver International Limited Five [Member]
Guarantor Obligations [Line Items]
Revolving lines of credit, capacity		$ 600.0
Unsecured and Committed | Voya Financial, Inc. / Roaring River LLC
Guarantor Obligations [Line Items]
Revolving lines of credit, capacity	425.0
Unsecured and Committed | Security Life of Denver International Ltd
Guarantor Obligations [Line Items]
Revolving lines of credit, capacity				$ 300.0
Parent Issuer
Guarantor Obligations [Line Items]
Revolving lines of credit, capacity	6,600.0
Long-term debt	3,018.0		$ 3,108.0
Parent Issuer | Unsecured and Committed
Guarantor Obligations [Line Items]
Revolving lines of credit, capacity	5,900.0
Parent Issuer | Unsecured and Committed | Voya Financial, Inc. And Security Life Of Denver International Limited Five [Member]
Guarantor Obligations [Line Items]
Revolving lines of credit, capacity	475.0
Financial Guarantee | Voya Financial Products Company, Inc.
Guarantor Obligations [Line Items]
Notional amount of guarantee obligation	1,000.0
Financial Guarantee | Parent Issuer | 8.424% Percent Lion Connecticut Holdings Inc. Debentures, Due 2027 | Debentures
Guarantor Obligations [Line Items]
Financial instruments subject to mandatory redemption, settlement terms, share value, par value	13.0
Financial Guarantee | Parent Issuer | Notes Payable
Guarantor Obligations [Line Items]
Minimum Net Capital Required for Entity						$ 124.0
Financial Guarantee | Parent Issuer | Voya Financial, Inc. / Roaring River IV, LLC | Notes Payable
Guarantor Obligations [Line Items]
Maintenance and reimbursement agreements						565.0
Financial Guarantee | Parent Issuer | Roaring River IV, Holding LLC | Notes Payable
Guarantor Obligations [Line Items]
Minimum Net Capital Required for Entity						79.0
Financial Guarantee | Parent Issuer | Roaring River IV, LLC | Notes Payable
Guarantor Obligations [Line Items]
Minimum Net Capital Required for Entity						$ 45.0
Financial Guarantee | Parent Issuer | Langhorne I, LLC | Notes Payable
Guarantor Obligations [Line Items]
Minimum Net Capital Required for Entity					$ 85.0
Financial Guarantee | Parent Issuer | Voya Financial, Inc. / Security Life of Denver Insurance Company | Notes Payable
Guarantor Obligations [Line Items]
Maintenance and reimbursement agreements	$ 21.0