Investments (excluding Consolidated Investment Entities) - Loans by Loan to Value (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 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	$ 6,904	$ 6,879
0% - 50%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans	$ 4,576	$ 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	$ 2,026	$ 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	$ 287	$ 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	$ 298	$ 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	153	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	714	723
Year of Origination 2019 | 0% - 50%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans	375	121
Year of Origination 2019 | 50% - 60%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans	218	138
Year of Origination 2019 | 60% - 70%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans	106	227
Year of Origination 2019 | 70% - 80%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans	15	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	460	513
Year of Origination 2018 | 0% - 50%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans	205	11
Year of Origination 2018 | 50% - 60%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans	158	141
Year of Origination 2018 | 60% - 70%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans	97	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	1,118	1,160
Year of Origination 2017 | 0% - 50%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans	668	153
Year of Origination 2017 | 50% - 60%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans	432	283
Year of Origination 2017 | 60% - 70%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans	18	697
Year of Origination 2017 | 70% - 80%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans	0	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	961	972
Year of Origination 2016 | 0% - 50%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans	626	122
Year of Origination 2016 | 50% - 60%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans	328	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	746	804
Year of Origination 2015 | 0% - 50%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans	625	39
Year of Origination 2015 | 50% - 60%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans	121	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	2,607	2,707
Year of Origination 2014 and prior | 0% - 50%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans	1,960	241
Year of Origination 2014 and prior | 50% - 60%
Schedule of Loans by Loan to Value Ratio [Line Items]
Commercial mortgage loans	616	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