Investments (excluding Consolidated Investment Entities) - Past due commercial mortgage loans (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Current
Financing Receivable, Past Due [Line Items]
Past due commercial mortgage loans	$ 6,895	$ 6,879
30-59 days past due
Financing Receivable, Past Due [Line Items]
Past due commercial mortgage loans	0	0
60-89 days past due
Financing Receivable, Past Due [Line Items]
Past due commercial mortgage loans	0	0
Greater than 90 days past due
Financing Receivable, Past Due [Line Items]
Past due commercial mortgage loans	9	0
Total
Financing Receivable, Past Due [Line Items]
Past due commercial mortgage loans	$ 6,904	$ 6,879