Related Party Transactions - Derivatives (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Related Party Transaction [Line Items]
Net realized gains (losses) on derivatives	$ (466.0)	$ (294.7)	$ (1,512.4)	$ (1,141.2)
ING Bank and ING V
Related Party Transaction [Line Items]
Notional amount of derivatives	439.2		439.2		2,100.0
Derivatives, fair value	6.7		6.7		15.6
Net realized gains (losses) on derivatives	1.6	17.7	(2.6)	25.9
ING Bank and ING V | Interest rate swaps
Related Party Transaction [Line Items]
Notional amount of derivatives	246.2		246.2		1,900.0
ING Bank and ING V | Equity options
Related Party Transaction [Line Items]
Notional amount of derivatives	193.0		193.0		265.7
ING V
Related Party Transaction [Line Items]
Maximum potential future net exposure on sale of credit default swaps	$ 500.0		$ 500.0		$ 1,000.0