Investments (excluding Consolidated Investment Entities) - Loans by Loan to Value (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Mar. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Schedule of Loans by Loan to Value Ratio [Line Items]
Targeted maximum amount of mortgage loans lended, percent of estimated fair value of underlying real estate		75.00%
Benchmark loan to value ratio, greater than indicates unpaid loan amount exceeds underlying collateral	100.00%	100.00%
Benchmark ratio	100.00%	100.00%
Commercial mortgage loans		$ 6,817	$ 6,879
0% - 50%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		$ 4,593	687
Loan to value ratio, minimum	0.00%	0.00%
Loan to value ratio, maximum	50.00%	50.00%
50% - 60%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		$ 1,948	1,723
Loan to value ratio, minimum	50.00%	50.00%
Loan to value ratio, maximum	60.00%	60.00%
60% - 70%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		$ 261	3,710
Loan to value ratio, minimum	60.00%	60.00%
Loan to value ratio, maximum	70.00%	70.00%
70% - 80%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		$ 15	703
Loan to value ratio, minimum	70.00%	70.00%
Loan to value ratio, maximum	80.00%	80.00%
80% and above
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		$ 0	56
Loan to value ratio, minimum	80.00%	80.00%
Year of Origination 2020
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		$ 332	0
Year of Origination 2020 | 0% - 50%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		117	0
Year of Origination 2020 | 50% - 60%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		187	0
Year of Origination 2020 | 60% - 70%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		28	0
Year of Origination 2020 | 70% - 80%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		0	0
Year of Origination 2020 | 80% and above
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		0	0
Year of Origination 2019
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		696	723
Year of Origination 2019 | 0% - 50%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		339	121
Year of Origination 2019 | 50% - 60%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		239	138
Year of Origination 2019 | 60% - 70%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		104	227
Year of Origination 2019 | 70% - 80%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		14	211
Year of Origination 2019 | 80% and above
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		0	26
Year of Origination 2018
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		445	513
Year of Origination 2018 | 0% - 50%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		204	11
Year of Origination 2018 | 50% - 60%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		167	141
Year of Origination 2018 | 60% - 70%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		74	188
Year of Origination 2018 | 70% - 80%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		0	159
Year of Origination 2018 | 80% and above
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		0	14
Year of Origination 2017
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		1,100	1,160
Year of Origination 2017 | 0% - 50%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		653	153
Year of Origination 2017 | 50% - 60%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		429	283
Year of Origination 2017 | 60% - 70%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		17	697
Year of Origination 2017 | 70% - 80%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		1	12
Year of Origination 2017 | 80% and above
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		0	15
Year of Origination 2016
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		953	972
Year of Origination 2016 | 0% - 50%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		620	122
Year of Origination 2016 | 50% - 60%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		326	221
Year of Origination 2016 | 60% - 70%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		7	579
Year of Origination 2016 | 70% - 80%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		0	50
Year of Origination 2016 | 80% and above
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		0	0
Year of Origination 2015
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		740	804
Year of Origination 2015 | 0% - 50%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		638	39
Year of Origination 2015 | 50% - 60%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		102	502
Year of Origination 2015 | 60% - 70%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		0	248
Year of Origination 2015 | 70% - 80%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		0	15
Year of Origination 2015 | 80% and above
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		0	0
Year of Origination 2014 and prior
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		2,551	2,707
Year of Origination 2014 and prior | 0% - 50%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		2,022	241
Year of Origination 2014 and prior | 50% - 60%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		498	438
Year of Origination 2014 and prior | 60% - 70%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		31	1,771
Year of Origination 2014 and prior | 70% - 80%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		0	256
Year of Origination 2014 and prior | 80% and above
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans		$ 0	$ 1