Financing Agreements - Credit Facilities (Details) $ in Millions	Sep. 30, 2015 USD ($)
Line of Credit Facility [Line Items]
Capacity	$ 7,466.7
Utilization	2,832.3
Unused Commitment	4,625.1
Unsecured and Committed
Line of Credit Facility [Line Items]
Capacity	7,260.0
Utilization	2,634.9
Unused Commitment	4,625.1
Unsecured and Committed \| Voya Financial, Inc.
Line of Credit Facility [Line Items]
Capacity	3,000.0
Utilization	470.8
Unused Commitment	2,529.2
Unsecured and Committed \| Security Life of Denver International Limited
Line of Credit Facility [Line Items]
Capacity	175.0
Utilization	157.0
Unused Commitment	18.0
Unsecured and Committed \| Voya Financial, Inc. And Langhorne I, LLC
Line of Credit Facility [Line Items]
Capacity	500.0
Utilization	0.0
Unused Commitment	500.0
Unsecured and Committed \| Security Life of Denver International Limited
Line of Credit Facility [Line Items]
Capacity	1,125.0
Utilization	233.6
Unused Commitment	891.4
Unsecured and Committed \| Voya Financial, Inc. And Security Life Of Denver International Limited
Line of Credit Facility [Line Items]
Capacity	475.0
Utilization	475.0
Unused Commitment	0.0
Unsecured and Committed \| Voya Financial, Inc. and Security Life Of Denver International Limited
Line of Credit Facility [Line Items]
Capacity	2,900.0
Unsecured and Committed \| Voya Financial Inc. / Roaring River LLC
Line of Credit Facility [Line Items]
Capacity	425.0
Utilization	207.5
Unused Commitment	217.5
Unsecured and Committed \| Voya Financial, Inc. / Roaring River II LLC
Line of Credit Facility [Line Items]
Capacity	995.0
Utilization	786.0
Unused Commitment	209.0
Unsecured and Committed \| Voya Financial, Inc. / Roaring River IV, LLC
Line of Credit Facility [Line Items]
Capacity	565.0
Utilization	305.0
Unused Commitment	260.0
Secured facilities
Line of Credit Facility [Line Items]
Capacity	205.0
Utilization	195.7
Unused Commitment	0.0
Secured facilities \| Voya Financial Inc.
Line of Credit Facility [Line Items]
Capacity	195.0
Utilization	195.0
Unused Commitment	0.0
Secured facilities \| Voya Financial, Inc.
Line of Credit Facility [Line Items]
Capacity	10.0
Utilization	0.7
Unused Commitment	0.0
Unsecured and Uncommitted
Line of Credit Facility [Line Items]
Capacity	1.7
Utilization	1.7
Unused Commitment	0.0
Unsecured and Uncommitted \| Voya Financial, Inc.
Line of Credit Facility [Line Items]
Capacity	1.7
Utilization	1.7
Unused Commitment	$ 0.0

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.16)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.16)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 20, 22

-Article 5

+ Details

Name:	us-gaap_LineOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant