Related Party Transactions - Derivatives (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Related Party Transaction [Line Items]
Net realized gains (losses) on derivatives	$ (221.3)	$ (762.0)
ING Bank and ING V
Related Party Transaction [Line Items]
Notional amount of derivatives	462.9		518.9
Derivatives, fair value	9.2		10.5
Net realized gains (losses) on derivatives	(0.7)	(1.4)
ING Bank and ING V | Interest rate swaps
Related Party Transaction [Line Items]
Notional amount of derivatives	214.3		328.8
ING Bank and ING V | Equity options
Related Party Transaction [Line Items]
Notional amount of derivatives	248.6		190.1
ING V
Related Party Transaction [Line Items]
Maximum potential future net exposure on sale of credit default swaps	$ 39.8		$ 43.5