Investments (excluding Consolidated Investment Entities) - Loans by Debt Service Coverage Ratio (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	$ 6,904	$ 6,879
>1.5x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Debt Service Coverage Ratio, minimum	150.00%	150.00%
>1.25x - 1.5x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Debt Service Coverage Ratio, minimum	125.00%	125.00%
Debt Service Coverage Ratio, maximum	150.00%	150.00%
>1.0x - 1.25x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Debt Service Coverage Ratio, minimum	100.00%	100.00%
Debt Service Coverage Ratio, maximum	125.00%	125.00%
Less than 1.0x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Debt Service Coverage Ratio, maximum	100.00%	100.00%
Year of Origination 2020
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	$ 298	$ 0
Year of Origination 2020 | >1.5x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	249	0
Year of Origination 2020 | >1.25x - 1.5x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	38	0
Year of Origination 2020 | >1.0x - 1.25x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	11	0
Year of Origination 2020 | Less than 1.0x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	0	0
Year of Origination 2020 | Commercial mortgage loans secured by land or construction loans
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	0	0
Year of Origination 2020 | Total
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	298	0
Year of Origination 2019
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	714	723
Year of Origination 2019 | >1.5x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	541	493
Year of Origination 2019 | >1.25x - 1.5x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	108	165
Year of Origination 2019 | >1.0x - 1.25x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	65	66
Year of Origination 2019 | Less than 1.0x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	0	0
Year of Origination 2019 | Commercial mortgage loans secured by land or construction loans
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	0	0
Year of Origination 2019 | Total
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	714	724
Year of Origination 2018
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	460	513
Year of Origination 2018 | >1.5x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	295	351
Year of Origination 2018 | >1.25x - 1.5x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	28	13
Year of Origination 2018 | >1.0x - 1.25x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	97	88
Year of Origination 2018 | Less than 1.0x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	40	61
Year of Origination 2018 | Commercial mortgage loans secured by land or construction loans
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	0	0
Year of Origination 2018 | Total
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	460	513
Year of Origination 2017
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	1,118	1,160
Year of Origination 2017 | >1.5x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	596	608
Year of Origination 2017 | >1.25x - 1.5x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	269	292
Year of Origination 2017 | >1.0x - 1.25x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	173	167
Year of Origination 2017 | Less than 1.0x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	80	93
Year of Origination 2017 | Commercial mortgage loans secured by land or construction loans
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	0	0
Year of Origination 2017 | Total
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	1,118	1,160
Year of Origination 2016
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	961	972
Year of Origination 2016 | >1.5x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	860	873
Year of Origination 2016 | >1.25x - 1.5x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	67	63
Year of Origination 2016 | >1.0x - 1.25x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	30	31
Year of Origination 2016 | Less than 1.0x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	4	4
Year of Origination 2016 | Commercial mortgage loans secured by land or construction loans
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	0	0
Year of Origination 2016 | Total
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	961	971
Year of Origination 2015
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	746	804
Year of Origination 2015 | >1.5x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	692	743
Year of Origination 2015 | >1.25x - 1.5x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	47	50
Year of Origination 2015 | >1.0x - 1.25x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	7	6
Year of Origination 2015 | Less than 1.0x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	0	6
Year of Origination 2015 | Commercial mortgage loans secured by land or construction loans
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	0	0
Year of Origination 2015 | Total
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	746	805
Year of Origination 2014 and prior
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	2,607	2,707
Year of Origination 2014 and prior | >1.5x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	2,197	2,265
Year of Origination 2014 and prior | >1.25x - 1.5x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	221	210
Year of Origination 2014 and prior | >1.0x - 1.25x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	119	139
Year of Origination 2014 and prior | Less than 1.0x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	70	92
Year of Origination 2014 and prior | Commercial mortgage loans secured by land or construction loans
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	0	0
Year of Origination 2014 and prior | Total
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	2,607	2,706
Total | >1.5x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	5,430	5,333
Total | >1.25x - 1.5x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	778	793
Total | >1.0x - 1.25x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	502	497
Total | Less than 1.0x
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	194	256
Total | Commercial mortgage loans secured by land or construction loans
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	0	0
Total | Total
Schedule of Loans by Debt Service Coverage Ratio [Line Items]
Commercial mortgage loans	$ 6,904	$ 6,879