Segment Information - Segment Information (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) segment	Sep. 30, 2019 USD ($) segment
Segment Reporting Information [Line Items]
Number of reportable segments | segment			2	1
Revenue, including adjustments	$ 232	$ 223	$ 716	$ 720
Total revenues	232	223	716	720
Total expenses	200	130	496	353
Income (loss) before income taxes and equity in net earnings of investees	32	93	220	367
Equity in net earnings of investees	7	0	3	3
Adjusted operating income (loss) before income taxes	39	93	223	370
Provision (benefit) for income taxes	(12)	16	18	66
Noncontrolling interests	3	0	5	0
Adjusted operating income (loss)	48	77	200	304
Net investment income	71	88	229	296
Interest expense	21	22	64	67
Non-cash compensation and operating expenses	14	10	44	33
Corporate
Segment Reporting Information [Line Items]
Revenue, including adjustments	12	1	8	2
Total revenues	12	1	8	2
Total expenses	32	31	99	93
Income (loss) before income taxes and equity in net earnings of investees	(20)	(30)	(91)	(91)
Equity in net earnings of investees	0	(1)	(5)	0
Adjusted operating income (loss) before income taxes	(20)	(31)	(96)	(91)
Provision (benefit) for income taxes	(2)	(3)	(13)	(12)
Noncontrolling interests	0	0	0	0
Adjusted operating income (loss)	(18)	(28)	(83)	(79)
Net investment income	0	1	1	3
Interest expense	24	23	72	69
Non-cash compensation and operating expenses	1	1	4	4
Other
Segment Reporting Information [Line Items]
Revenue, including adjustments	21	1	44	23
Total revenues	17	0	33	21
Total expenses	5	2	8	16
Income (loss) before income taxes and equity in net earnings of investees	12	(2)	25	5
Equity in net earnings of investees	(13)	0	(29)	0
Adjusted operating income (loss) before income taxes	(1)	(2)	(4)	5
Provision (benefit) for income taxes	(1)	0	(2)	1
Noncontrolling interests	3	0	5	0
Adjusted operating income (loss)	(3)	(2)	(7)	4
Net investment income	(4)	(2)	(12)	(5)
Interest expense	(3)	(1)	(8)	(2)
Non-cash compensation and operating expenses	0	0	0	0
Intersegment Eliminations
Segment Reporting Information [Line Items]
Revenue, including adjustments	(4)	(1)	(11)	(2)
Insurance | Operating Segments
Segment Reporting Information [Line Items]
Revenue, including adjustments	186	221	623	695
Total revenues	189	222	631	697
Total expenses	134	97	308	244
Income (loss) before income taxes and equity in net earnings of investees	55	125	323	453
Equity in net earnings of investees	20	1	37	3
Adjusted operating income (loss) before income taxes	75	126	360	456
Provision (benefit) for income taxes	(6)	19	40	77
Noncontrolling interests	0	0	0	0
Adjusted operating income (loss)	81	107	320	379
Net investment income	75	89	240	298
Interest expense	0	0	0	0
Non-cash compensation and operating expenses	9	9	27	29
Insurance | Intersegment Eliminations
Segment Reporting Information [Line Items]
Revenue, including adjustments	3	1	8	2
Asset Management | Operating Segments
Segment Reporting Information [Line Items]
Revenue, including adjustments	13	0	41	0
Total revenues	14	0	44	0
Total expenses	29	0	81	0
Income (loss) before income taxes and equity in net earnings of investees	(15)	0	(37)	0
Equity in net earnings of investees	0	0	0	0
Adjusted operating income (loss) before income taxes	(15)	0	(37)	0
Provision (benefit) for income taxes	(3)	0	(7)	0
Noncontrolling interests	0	0	0	0
Adjusted operating income (loss)	(12)	0	(30)	0
Net investment income	0	0	0	0
Interest expense	0	0	0	0
Non-cash compensation and operating expenses	4	0	13	0
Asset Management | Intersegment Eliminations
Segment Reporting Information [Line Items]
Revenue, including adjustments	$ 1	$ 0	$ 3	$ 0