Schedule II - Condensed Financial Information of Parent - Statements of Cash Flow (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash Flows from Operating Activities:
Net income (loss) available to ING U.S., Inc.'s common shareholder	$ 2,299.7	$ 600.5	$ 473.0
Equity in earnings of subsidiary	0	0	0
Net accretion/amortization of discount/premium	13.6	54.9	70.8
Deferred income tax (benefit) expense	(1,840.6)	(110.8)	(44.5)
Net realized capital losses	(894.4)	(2,534.8)	(1,280.8)
Change in:
Other receivables and asset accruals	39.5	24.8	125.4
Other, net	9.3	(16.1)	(19.0)
Net cash provided by operating activities	3,628.6	3,263.4	3,282.1
Cash Flows from Investing Activities:
Equity securities, available-for-sale	70.0	51.6	66.8
Equity securities, available-for-sale	(28.4)	(47.6)	(41.8)
Derivatives, net	(1,117.4)	(2,623.7)	(1,395.8)
Other investments, net	33.0	53.0	43.4
Short-term intercompany loans issued to subsidiaries with maturities more than three months	0	0
Net maturity of intercompany loans to subsidiaries	0	0	0
Return of capital contributions and dividends from subsidiaries	0	0	0
Capital contributions to subsidiaries	0	0	0
Collateral received (delivered), net	401.5	(629.3)	139.9
Net cash used in investing activities	(3,313.9)	(1,885.6)	(2,375.9)
Cash Flows from Financing Activities:
Short-term debt	0	(171.6)	(309.1)
Proceeds from issuance of long-term debt	0	2,146.8	3,049.6
Repayment of long-term debt	0	(2,697.4)	(902.5)
Debt issuance costs	(16.8)	(26.5)	(38.8)
Payments for Maturity of Long-Term Intercompany Loans	0	0
Net (repayments of) proceeds from loans to subsidiaries	0	0	0
Proceeds from issuance of common stock	0	571.6	0
Share-based compensation	(16.9)	0	0
Common stock acquired - Share repurchase	(789.4)	0	0
Dividends paid	(10.1)	(5.2)	0
Net cash (used in) provided by financing activities	(624.6)	(323.8)	242.6
Net increase in cash and cash equivalents	(309.9)	1,054.0	1,148.8
Cash and cash equivalents, beginning of year	2,840.8	1,786.8	638.0
Cash and cash equivalents, end of year	2,530.9	2,840.8	1,786.8
Supplemental cash flow information:
Income taxes paid, net	44.5	44.6	3.5
Interest paid	178.6	147.4	114.9
Parent Issuer
Cash Flows from Operating Activities:
Net income (loss) available to ING U.S., Inc.'s common shareholder	2,299.7	600.5	473.0
Equity in earnings of subsidiary	(2,226.8)	(529.1)	(213.3)
Net accretion/amortization of discount/premium	0.4	0.3	0
Deferred income tax (benefit) expense	(141.0)	(77.0)	135.6
Net realized capital losses	(3.4)	(39.2)	0
Change in:
Other receivables and asset accruals	145.9	191.8	(162.4)
Due from subsidiaries	3.8	1.1	(10.2)
Due to subsidiaries	6.5	(22.9)	(0.8)
Other payables and accruals	5.1	7.1	(162.2)
Other, net	(4.5)	(7.6)	0
Net cash provided by operating activities	85.7	203.4	59.7
Cash Flows from Investing Activities:
Equity securities, available-for-sale	18.7	14.5	27.2
Equity securities, available-for-sale	(25.0)	(19.6)	(14.0)
Derivatives, net	1.3	(6.6)	0
Other investments, net	0	0	0
Short-term intercompany loans issued to subsidiaries with maturities more than three months	0.9	2.3	0
Net maturity of intercompany loans to subsidiaries	41.5	(136.6)	102.3
Return of capital contributions and dividends from subsidiaries	902.0	1,434.0	813.0
Capital contributions to subsidiaries	(150.0)	(2,062.0)	(400.0)
Collateral received (delivered), net	0	27.7	7.2
Net cash used in investing activities	789.4	(746.3)	535.7
Cash Flows from Financing Activities:
Short-term debt	0	(171.6)	(309.1)
Proceeds from issuance of long-term debt	0	2,146.8	3,048.5
Repayment of long-term debt	0	(1,370.4)	(902.5)
Debt issuance costs	(16.8)	(26.5)	(38.8)
Payments for Maturity of Long-Term Intercompany Loans	0	0
Net (repayments of) proceeds from loans to subsidiaries	0	(319.1)	(2,037.3)
Proceeds from issuance of common stock	0	571.6	0
Share-based compensation	(16.9)	0	0
Common stock acquired - Share repurchase	(789.4)	0	0
Dividends paid	(10.1)	(5.2)	0
Net cash (used in) provided by financing activities	(833.2)	825.6	(239.2)
Net increase in cash and cash equivalents	41.9	282.7	356.2
Cash and cash equivalents, beginning of year	640.2	357.5	1.3
Cash and cash equivalents, end of year	682.1	640.2	357.5
Supplemental cash flow information:
Income taxes paid, net	42.8	43.0	5.2
Interest paid	141.1	90.6	33.4
Subsidiary Guarantor
Cash Flows from Operating Activities:
Net income (loss) available to ING U.S., Inc.'s common shareholder	772.5	847.0	752.3
Equity in earnings of subsidiary	(733.2)	(866.0)	(811.1)
Net realized capital losses	(0.4)	0	0
Change in:
Net cash provided by operating activities	160.1	83.3	50.5
Cash Flows from Investing Activities:
Equity securities, available-for-sale	13.1	14.0	12.0
Equity securities, available-for-sale	0	(11.1)	(17.5)
Derivatives, net	0	0	0
Other investments, net	(11.0)	0	1.3
Short-term intercompany loans issued to subsidiaries with maturities more than three months	0	0
Net maturity of intercompany loans to subsidiaries	0	58.0	(33.5)
Return of capital contributions and dividends from subsidiaries	780.0	1,077.0	720.0
Capital contributions to subsidiaries	(171.0)	(0.3)	0
Collateral received (delivered), net	0	0	0
Net cash used in investing activities	611.1	1,137.6	682.3
Cash Flows from Financing Activities:
Short-term debt		0	0
Proceeds from issuance of long-term debt		0	0
Repayment of long-term debt		(638.6)	0
Debt issuance costs	0	0	0
Payments for Maturity of Long-Term Intercompany Loans	0	0
Net (repayments of) proceeds from loans to subsidiaries	24.3	125.4	0
Proceeds from issuance of common stock		0
Share-based compensation	0
Common stock acquired - Share repurchase	0
Dividends paid	0	0
Net cash (used in) provided by financing activities	(770.7)	(1,220.2)	(733.0)
Net increase in cash and cash equivalents	0.5	0.7	(0.2)
Cash and cash equivalents, beginning of year	1.1	0.4	0.6
Cash and cash equivalents, end of year	1.6	1.1	0.4
Non-Guarantor Subsidiaries
Cash Flows from Operating Activities:
Net income (loss) available to ING U.S., Inc.'s common shareholder	2,134.6	548.1	221.6
Equity in earnings of subsidiary	0	0	0
Net realized capital losses	(890.6)	(2,495.6)	(1,280.8)
Change in:
Net cash provided by operating activities	3,565.8	3,076.7	3,264.9
Cash Flows from Investing Activities:
Equity securities, available-for-sale	38.2	23.1	27.6
Equity securities, available-for-sale	(3.4)	(16.9)	(10.3)
Derivatives, net	(1,118.7)	(2,617.1)	(1,395.8)
Other investments, net	44.0	53.0	42.1
Short-term intercompany loans issued to subsidiaries with maturities more than three months	0	0
Net maturity of intercompany loans to subsidiaries	0	261.1	2,070.8
Return of capital contributions and dividends from subsidiaries	0	0	0
Capital contributions to subsidiaries	0	0	0
Collateral received (delivered), net	401.5	(657.0)	132.7
Net cash used in investing activities	(3,311.0)	(1,643.4)	(321.3)
Cash Flows from Financing Activities:
Short-term debt		0	0
Proceeds from issuance of long-term debt		0	1.1
Repayment of long-term debt		(688.4)	0
Debt issuance costs	0	0	0
Payments for Maturity of Long-Term Intercompany Loans	0.9	2.3
Net (repayments of) proceeds from loans to subsidiaries	(65.8)	11.2	(102.3)
Proceeds from issuance of common stock		0
Share-based compensation	0
Common stock acquired - Share repurchase	0
Dividends paid	0	0
Net cash (used in) provided by financing activities	(607.1)	(662.7)	(2,150.8)
Net increase in cash and cash equivalents	(352.3)	770.6	792.8
Cash and cash equivalents, beginning of year	2,199.5	1,428.9	636.1
Cash and cash equivalents, end of year	1,847.2	2,199.5	1,428.9
Consolidating Adjustments
Cash Flows from Operating Activities:
Net income (loss) available to ING U.S., Inc.'s common shareholder	(2,907.1)	(1,395.1)	(973.9)
Equity in earnings of subsidiary	2,960.0	1,395.1	1,024.4
Net realized capital losses	0	0	0
Change in:
Net cash provided by operating activities	(183.0)	(100.0)	(93.0)
Cash Flows from Investing Activities:
Equity securities, available-for-sale	0	0	0
Equity securities, available-for-sale	0	0	0
Derivatives, net	0	0	0
Other investments, net	0	0	0
Short-term intercompany loans issued to subsidiaries with maturities more than three months	(0.9)	(2.3)
Net maturity of intercompany loans to subsidiaries	(41.5)	(182.5)	(2,139.6)
Return of capital contributions and dividends from subsidiaries	(1,682.0)	(2,511.0)	(1,533.0)
Capital contributions to subsidiaries	321.0	2,062.3	400.0
Collateral received (delivered), net	0	0	0
Net cash used in investing activities	(1,403.4)	(633.5)	(3,272.6)
Cash Flows from Financing Activities:
Short-term debt		0	0
Proceeds from issuance of long-term debt		0	0
Repayment of long-term debt		0	0
Debt issuance costs	0	0	0
Payments for Maturity of Long-Term Intercompany Loans	(0.9)	(2.3)
Net (repayments of) proceeds from loans to subsidiaries	41.5	182.5	2,139.6
Proceeds from issuance of common stock		0
Share-based compensation	0
Common stock acquired - Share repurchase	0
Dividends paid	0	0
Net cash (used in) provided by financing activities	1,586.4	733.5	3,365.6
Net increase in cash and cash equivalents	0	0	0
Cash and cash equivalents, beginning of year	0	0	0
Cash and cash equivalents, end of year	$ 0	$ 0	$ 0