Segments - Operating Revenues (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Total revenues	$ 1,810	$ 1,875	$ 1,969	$ 1,822	$ 1,851	$ 1,890	$ 1,761	$ 1,661	$ 7,476	$ 7,163	$ 7,229
Operating Segments
Segment Reporting Information [Line Items]
Total revenues									5,510	5,350	5,183
Segment Reconciling Items
Segment Reporting Information [Line Items]
Total revenues									1,966	1,813	2,046
Net realized investment gains (losses) and related charges and adjustments									18	(148)	(132)
Gain (loss) on change in fair value of derivatives related to guaranteed benefits									(13)	63	46
Revenues related to business exited through reinsurance or divestment									1,531	1,446	1,618
Revenues attributable to noncontrolling interest									109	214	321
Other adjustments									321	238	193
Retirement | Operating Segments
Segment Reporting Information [Line Items]
Total revenues									2,712	2,727	2,538
Investment Management | Operating Segments
Segment Reporting Information [Line Items]
Total revenues									675	683	731
Investment Management | Intersegment
Segment Reporting Information [Line Items]
Total revenues									104	101	103
Employee Benefits | Operating Segments
Segment Reporting Information [Line Items]
Total revenues									2,026	1,849	1,767
Corporate
Segment Reporting Information [Line Items]
Total revenues									$ 97	$ 91	$ 147