Related Party Transactions (Details) (USD $)	3 Months Ended		9 Months Ended				3 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011	Mar. 31, 2009 Alt-A RMBS	Mar. 31, 2009 Alt-A RMBS Dutch State	Mar. 31, 2009 Alt-A RMBS Dutch State ING Bank, FSB and Certain Subsidiaries of ING U.S. Inc.	Sep. 30, 2012 Designated Securities Portfolio Expected Plan	Sep. 30, 2012 Designated Securities Portfolio Dutch State Expected Plan ING Bank	Mar. 31, 2009 Designated Securities Portfolio ING Support Holding
Related Party Transaction [Line Items]
Percentage of investments covered by facility							80.00%
Aggregate book value of transferred assets							$ 1,400,000,000	$ 36,000,000,000
Percentage of participation in results of investment portfolio						20.00%	80.00%				80.00%
Discount of par value (as a percent)							10.00%
Ownership of investment portfolio (as a percent)						100.00%			20.00%
Loan receivable, net fees incurred	700,000	800,000	2,000,000	2,300,000
Dutch State Obligation, carrying value	$ 545,400,000		$ 545,400,000		$ 658,200,000
Legal title to be transferred (as a percent)										80.00%