Financing Agreements - Long-term Debt (Details) - USD ($)			12 Months Ended
	Jan. 23, 2018	May 16, 2013	Dec. 31, 2017	Jan. 24, 2018	Jul. 05, 2017	Dec. 31, 2016	Jun. 13, 2016	Mar. 17, 2015	Jul. 26, 2013	Feb. 11, 2013	Jul. 13, 2012	Jun. 16, 2007
Debt Instrument [Line Items]
Minimum net worth required for compliance								$ 3,000,000,000
Total			$ 3,460,000,000			$ 3,550,000,000
Current portion of long-term debt			337,000,000			0
Long-term debt			3,123,000,000			$ 3,550,000,000
1.00% Windsor Property Loan
Debt Instrument [Line Items]
Debt Instrument, Collateral Amount			$ 5,000,000
debt instrument, default penalty, percentage			2.50%
2.9% Senior Notes, due 2018
Debt Instrument [Line Items]
Annual interest rate on loan			2.90%			2.90%
Debentures | 7.25% Voya Holdings Inc. debentures, due 2023(1)
Debt Instrument [Line Items]
Total			$ 143,000,000			$ 143,000,000
Annual interest rate on loan			7.25%			7.25%
Debentures | 7.63% Voya Holdings Inc. debentures, due 2026(1)
Debt Instrument [Line Items]
Total			$ 186,000,000			$ 186,000,000
Annual interest rate on loan			7.63%			7.63%
Debentures | 6.97% Voya Holdings Inc. debentures, due 2036(1)
Debt Instrument [Line Items]
Total			$ 94,000,000			$ 94,000,000
Annual interest rate on loan			6.97%			6.97%
Notes Payable | 8.42% Equitable of Iowa Companies Capital Trust II Notes, due 2027
Debt Instrument [Line Items]
Total			$ 14,000,000			$ 14,000,000
Annual interest rate on loan			8.42%			8.42%
Property Loan | 1.00% Windsor Property Loan
Debt Instrument [Line Items]
Amount of unsecured notes issued												$ 10,000,000
Total			$ 5,000,000			$ 5,000,000
Annual interest rate on loan			1.00%			1.00%
Senior Notes
Debt Instrument [Line Items]
Annual interest rate on loan								1.875%
Senior Notes | 5.5% Senior Notes, due 2022
Debt Instrument [Line Items]
Amount of unsecured notes issued											$ 850,000,000
Total			$ 361,000,000			$ 361,000,000
Annual interest rate on loan			5.50%			5.50%					5.50%
Senior Notes | 2.9% Senior Notes, due 2018
Debt Instrument [Line Items]
Amount of unsecured notes issued			$ 337,000,000							$ 1,000,000,000
Total			$ 337,000,000			$ 825,000,000
Annual interest rate on loan			2.90%			2.90%				2.90%
Senior Notes | 5.7% Senior Notes, due 2043
Debt Instrument [Line Items]
Amount of unsecured notes issued									$ 400,000,000
Total			$ 395,000,000			$ 394,000,000
Annual interest rate on loan			5.70%			5.70%			5.70%
Senior Notes | 3.65% Senior Notes, due 2026
Debt Instrument [Line Items]
Amount of unsecured notes issued							$ 500,000,000
Total			$ 495,000,000			$ 494,000,000
Annual interest rate on loan			3.65%			3.65%	3.65%
Senior Notes | 4.8% Senior Notes, due 2046
Debt Instrument [Line Items]
Amount of unsecured notes issued							$ 300,000,000
Total			$ 296,000,000			$ 296,000,000
Annual interest rate on loan			4.80%			4.80%	4.80%
Senior Notes | 3.125% Senior Notes, due 2024
Debt Instrument [Line Items]
Amount of unsecured notes issued					$ 400,000,000
Total			$ 396,000,000			$ 0
Annual interest rate on loan			3.125%		3.125%	0.00%
Junior Subordinated Notes | 5.65% Fixed-to-Floating Rate Junior Subordinated Notes, due 2053
Debt Instrument [Line Items]
Debt Instrument, Aggregate Principal Amount to Remain Outstanding after Effect of Redemption			$ 25,000,000
Amount of unsecured notes issued		$ 750,000,000
Total			$ 738,000,000			$ 738,000,000
Annual interest rate on loan		5.65%	5.65%			5.65%
Description of variable rate basis			LIBOR
Basis spread		3.58%
Subsequent event | Junior Subordinated Notes | 4.7% Fixed-to-Floating Rate Junior Subordinated Notes, due 2048
Debt Instrument [Line Items]
Debt Instrument, Aggregate Principal Amount to Remain Outstanding after Effect of Redemption	$ 25,000,000
Amount of unsecured notes issued	$ 350,000,000
debt redemption price, percentage	102.00%
Annual interest rate on loan	4.70%
Description of variable rate basis	LIBOR
Basis spread	2.084%
Revolving Credit Agreement | Subsequent event
Debt Instrument [Line Items]
Minimum net worth required for compliance				$ 6,000,000,000