Investments (excluding Consolidated Investment Entities) - OTTI OCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Balance, beginning	$ 11	$ 21	$ 21
Additional credit impairments:
On securities not previously impaired	0	0	8
Reductions:
Securities sold, matured, prepaid or paid down	3	10	8
Balance, ending	$ 8	$ 11	$ 21