Schedule II - Condensed Financial Information of Parent - Balance Sheets (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Investments:
Equity securities, available-for-sale, at fair value	$ 380.0	$ 258.0
Short-term investments	471.0	391.0
Derivatives	397.0	737.0
Investments in subsidiaries	0.0	0.0
Total investments	66,087.0	63,783.0
Cash and cash equivalents	1,218.0	2,096.0	$ 1,817.0
Short-term investments under securities loan agreements, including collateral delivered	1,626.0	586.0
Loans to subsidiaries and affiliates	0.0	0.0
Due from subsidiaries and affiliates	0.0	0.0
Current income taxes	4.0	164.0
Deferred income taxes	781.0	1,570.0
Other assets	1,310.0	1,486.0
Total assets	222,532.0	214,585.0
Liabilities and Shareholders' Equity:
Short-term debt	337.0	0.0
Long-term debt	3,123.0	3,550.0
Derivatives	149.0	297.0
Due to subsidiaries and affiliates	0.0	0.0
Other liabilities	2,076.0	2,023.0
Total liabilities	211,493.0	200,617.0
Shareholders' equity:
Common stock ($0.01 par value per share; 900,000,000 shares authorized; 270,078,294 and 268,079,931 shares issued as of 2017 and 2016, respectively; 171,982,673 and 194,639,273 shares outstanding as of 2017 and 2016, respectively)	3.0	3.0
Treasury stock (at cost; 98,095,621 and 73,440,658 shares as of 2017 and 2016, respectively)	(3,827.0)	(2,796.0)
Additional paid-in capital	23,821.0	23,609.0
Accumulated other comprehensive income (loss)	2,731.0	1,921.0	1,425.0
Retained earnings (deficit):
Unappropriated	(12,719.0)	(9,742.0)
Total Voya Financial, Inc. shareholders' equity	10,009.0	12,995.0
Total liabilities and shareholder's equity	222,532.0	214,585.0
Parent Issuer
Investments:
Equity securities, available-for-sale, at fair value	115.0	93.0
Short-term investments	212.0	212.0
Derivatives	49.0	56.0
Investments in subsidiaries	12,293.0	14,743.0
Total investments	12,669.0	15,104.0
Cash and cash equivalents	244.0	257.0	$ 378.0
Short-term investments under securities loan agreements, including collateral delivered	11.0	11.0
Loans to subsidiaries and affiliates	191.0	278.0
Due from subsidiaries and affiliates	2.0	3.0
Current income taxes	0.0	31.0
Deferred income taxes	406.0	527.0
Other assets	16.0	21.0
Total assets	13,539.0	16,232.0
Liabilities and Shareholders' Equity:
Short-term debt	755.0	11.0
Long-term debt	2,681.0	3,108.0
Derivatives	49.0	56.0
Due to subsidiaries and affiliates	1.0	0.0
Other liabilities	44.0	62.0
Total liabilities	3,530.0	3,237.0
Shareholders' equity:
Common stock ($0.01 par value per share; 900,000,000 shares authorized; 270,078,294 and 268,079,931 shares issued as of 2017 and 2016, respectively; 171,982,673 and 194,639,273 shares outstanding as of 2017 and 2016, respectively)	3.0	3.0
Treasury stock (at cost; 98,095,621 and 73,440,658 shares as of 2017 and 2016, respectively)	(3,827.0)	(2,796.0)
Additional paid-in capital	23,821.0	23,609.0
Accumulated other comprehensive income (loss)	2,731.0	1,921.0
Retained earnings (deficit):
Unappropriated	(12,719.0)	(9,742.0)
Total Voya Financial, Inc. shareholders' equity	10,009.0	12,995.0
Total liabilities and shareholder's equity	$ 13,539.0	$ 16,232.0