Financing Agreements - Credit Facilities (Details) (USD $)	Sep. 30, 2014
Line of Credit Facility [Line Items]
Capacity	$ 9,977,900,000
Utilization	5,674,400,000
Unused Commitment	4,298,200,000
ING Bank
Line of Credit Facility [Line Items]
Capacity	1,275,000,000
Utilization	734,300,000
Unused Commitment	540,700,000
Secured facilities
Line of Credit Facility [Line Items]
Capacity	265,000,000
Utilization	259,700,000
Unused Commitment	0
Secured and Uncommitted | Voya Financial, Inc. Three
Line of Credit Facility [Line Items]
Capacity	10,000,000
Utilization	4,700,000
Unused Commitment	0
Committed and Conditional | ReliaStar Life Insurance Company
Line of Credit Facility [Line Items]
Capacity	255,000,000
Utilization	255,000,000
Unused Commitment	0
Unsecured and Uncommitted
Line of Credit Facility [Line Items]
Capacity	1,700,000
Utilization	1,700,000
Unused Commitment	0
Unsecured and Uncommitted | Voya Financial, Inc. Two
Line of Credit Facility [Line Items]
Capacity	1,700,000
Utilization	1,700,000
Unused Commitment	0
Unsecured and Committed
Line of Credit Facility [Line Items]
Capacity	9,711,200,000
Utilization	5,413,000,000
Unused Commitment	4,298,200,000
Unsecured and Committed | Voya Financial, Inc.
Line of Credit Facility [Line Items]
Capacity	3,000,000,000
Utilization	684,900,000
Unused Commitment	2,315,100,000
Unsecured and Committed | Security Life of Denver International Limited
Line of Credit Facility [Line Items]
Capacity	150,000,000
Utilization	150,000,000
Unused Commitment	0
Unsecured and Committed | Voya Financial, Inc./ Langhorne I, LLC
Line of Credit Facility [Line Items]
Capacity	500,000,000
Utilization	0
Unused Commitment	500,000,000
Unsecured and Committed | Voya Financial, Inc. / Security Life of Denver International Limited Two [Member]
Line of Credit Facility [Line Items]
Capacity	750,000,000
Utilization	750,000,000
Unused Commitment	0
Unsecured and Committed | Security Life of Denver International Limited
Line of Credit Facility [Line Items]
Capacity	1,125,000,000
Utilization	700,100,000
Unused Commitment	424,900,000
Unsecured and Committed | Voya Financial, Inc. / Security Life of Denver International Limited Three [Member]
Line of Credit Facility [Line Items]
Capacity	750,000,000
Utilization	750,000,000
Unused Commitment	0
Unsecured and Committed | Voya Financial, Inc. / Security Life of Denver International Limited Four [Member]
Line of Credit Facility [Line Items]
Capacity	250,000,000
Utilization	250,000,000
Unused Commitment	0
Unsecured and Committed | Voya Financial, Inc. / Security Life of Denver International Limited Five [Member]
Line of Credit Facility [Line Items]
Capacity	475,000,000
Utilization	475,000,000
Unused Commitment	0
Unsecured and Committed | Voya Financial, Inc. / Roaring River II LLC
Line of Credit Facility [Line Items]
Capacity	995,000,000
Utilization	660,000,000
Unused Commitment	335,000,000
Unsecured and Committed | Voya Financial, Inc. / Roaring River III LLC [Member]
Line of Credit Facility [Line Items]
Capacity	1,151,200,000
Utilization	696,000,000
Unused Commitment	455,200,000
Unsecured and Committed | Voya Financial, Inc./ Roaring River IV LLC
Line of Credit Facility [Line Items]
Capacity	565,000,000
Utilization	297,000,000
Unused Commitment	$ 268,000,000