Investments (excluding Consolidated Investment Entities) - Allowance for Losses for Commercial Mortgage Loans (Details) $ in Millions	3 Months Ended
	Mar. 31, 2020 USD ($)
Allowance for Loan and Lease Losses [Roll Forward]
Balance as of January 1	$ 0
Credit losses on securities for which credit losses were not previously recorded	7
Initial allowance for credit losses recognized on financial assets accounted for as PCD	0
Increase (decrease) on securities with allowance recorded in previous period	0
Write-offs	0
Recoveries of amounts previously written off	0
Balance as of March 31	7
Commercial Portfolio Segment
Allowance for Loan and Lease Losses [Roll Forward]
Balance as of January 1	16
Credit losses on securities for which credit losses were not previously recorded	1
Initial allowance for credit losses recognized on financial assets accounted for as PCD	0
Increase (decrease) on securities with allowance recorded in previous period	5
Provision for expected credit losses	22
Write-offs	0
Recoveries of amounts previously written off	0
Balance as of March 31	$ 22