Segment Information - Reconciliation of Segment Net Investment Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Net investment income	$ 4,522	$ 4,004	$ 3,269
Operating Segments | Retirement Services
Segment Reporting Information [Line Items]
Net investment income	5,062	4,188	3,241
Operating Segments | Corporate and Other
Segment Reporting Information [Line Items]
Net investment income	117	44	182
Non-operating adjustments
Segment Reporting Information [Line Items]
Reinsurance Embedded Derivative Gain (Loss)	(680)	(301)	(191)
Income (Loss) from Variable Interest Entities, Net	(80)	(37)	(77)
Alternative Income Gain (Loss)	(1)	34	20
Noncontrolling interests	61	0	0
Other Adjustment to Net Investment Income	$ 43	$ 76	$ 94