Financing Agreements (Details) (USD $) In Millions, unless otherwise specified			0 Months Ended			3 Months Ended	9 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Jan. 31, 2004 ING U.S. Inc.	Jun. 30, 2012 ING U.S. Inc.	Dec. 31, 2011 ING U.S. Inc.	Sep. 30, 2011 Net investment income ING U.S. Inc.	Sep. 30, 2012 Net investment income ING U.S. Inc.	Sep. 30, 2011 Net investment income ING U.S. Inc.	Apr. 20, 2012 Senior Unsecured Credit Facility [Member]
Related Party Transaction [Line Items]
Maximum borrowing capacity of each party			3.00%
Variable rate basis on reciprocal loans			ING U.S., Inc.'s cost of funds
Basis spread on reciprocal loans			0.15%
Interest income on reciprocal loans						$ 0.2	$ 0.4	$ 0.6
Short-term loan to affiliate	0	535.9		0	535.9
Senior Unsecured Credit Facility current borrowing capacity									$ 5,000.0