Related Party Transactions - Derivatives (Details) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended			3 Months Ended			9 Months Ended		3 Months Ended		9 Months Ended									0 Months Ended
	Sep. 08, 2014	Mar. 31, 2014	Mar. 25, 2014	Sep. 30, 2014	Jun. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 ING Bank and ING V	Sep. 30, 2013 ING Bank and ING V	Sep. 30, 2014 ING Bank and ING V	Sep. 30, 2013 ING Bank and ING V	Dec. 31, 2013 ING Bank and ING V	Sep. 30, 2014 ING Bank and ING V Interest rate swaps	Dec. 31, 2013 ING Bank and ING V Interest rate swaps	Sep. 30, 2014 ING Bank and ING V Equity options	Dec. 31, 2013 ING Bank and ING V Equity options	Sep. 30, 2014 ING V	Dec. 31, 2013 ING V	Sep. 08, 2014 Voya Financial, Inc.	Mar. 25, 2014 Voya Financial, Inc.
Related Party Transaction [Line Items]
Notional amount of derivatives									$ 319.4		$ 319.4		$ 518.9	$ 82.6	$ 328.8	$ 236.8	$ 190.1
Derivatives, fair value									10.3		10.3		10.5
Net realized gains (losses) on derivatives				314.6		(466.0)	(379.2)	(1,512.4)	0	1.6	3.9	(2.6)
Maximum potential future net exposure on sale of credit default swaps																		35.3	43.5
Shares repurchased	7,722,007	250,000	7,255,853		875,558															7,722,007	7,255,853
Shares repurchased, value	$ 300.0	$ 8.9	$ 250.0		$ 30.5		$ 609.4	$ 0