Fair Value Fair Value - Reconciliation of Level 3 Financial Instruments (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	$ 10,447	$ 7,112	$ 8,958	$ 5,528
Total realized and unrealized gains (losses) included in income	650	369	1,019	1,776
Total realized and unrealized gains (losses) included in OCI	109	34	(95)	98
Purchases, issuances, sales and settlements, net	1,267	1,236	2,710	1,636
Transfers in	33	(339)	(86)	(626)
Transfers (out)	(429)	(453)	(340)	(891)
Ending balance	12,506	8,412	12,506	8,412
Total gains (losses) included in earnings	19	3	86	(2)
Beginning balance	(14,802)	(13,264)	(14,296)	(11,078)
Total realized and unrealized gains (losses) included in income	(613)	(421)	(1,278)	(2,326)
Total realized and unrealized gains (losses) included in OCI	0	0	0	0
Purchases, issuances, sales and settlements, net	(48)	(103)	111	(384)
Transfers in	0	0	0	0
Transfers (out)	0	0	0	0
Ending balance	(15,463)	(13,788)	(15,463)	(13,788)
Total gains (losses) included in earnings	0	0	(2)	0
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0		0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	121		(93)
Reinsurance Recoverable Including Reinsurance Premium Paid [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	2,099	1,834	1,821	1,676
Total realized and unrealized gains (losses) included in income	56	120	334	278
Total realized and unrealized gains (losses) included in OCI	0	0	0	0
Purchases, issuances, sales and settlements, net	0	0	0	0
Transfers in	0	0	0	0
Ending balance	2,155	1,954	2,155	1,954
Total gains (losses) included in earnings	0	0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0		0
Short-term Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	114	45	41	0
Total realized and unrealized gains (losses) included in income	0	0	0	0
Total realized and unrealized gains (losses) included in OCI	0	0	0	0
Purchases, issuances, sales and settlements, net	(16)	181	(31)	226
Transfers in	(88)	0	0	0
Ending balance	10	226	10	226
Total gains (losses) included in earnings	0	0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0		0
Mortgage loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	25	32	27	32
Total realized and unrealized gains (losses) included in income	0	0	0	1
Total realized and unrealized gains (losses) included in OCI	0	0	0	0
Purchases, issuances, sales and settlements, net	(6)	(4)	(8)	(5)
Transfers in	0	0	0	0
Transfers (out)	0	0	0	0
Ending balance	19	28	19	28
Total gains (losses) included in earnings	0	0	0	1
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0		0
Investment funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	17	25	22	29
Total realized and unrealized gains (losses) included in income	0	(1)	(5)	(2)
Total realized and unrealized gains (losses) included in OCI	0	0	0	0
Purchases, issuances, sales and settlements, net	0	(2)	0	(5)
Transfers in	0	0	0	0
Transfers (out)		0		0
Ending balance	17	22	17	22
Total gains (losses) included in earnings	0	(1)	(4)	(2)
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0		0
Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	6	3	3	3
Total realized and unrealized gains (losses) included in income	0	0	3	0
Total realized and unrealized gains (losses) included in OCI	0	0	0	0
Purchases, issuances, sales and settlements, net	10	0	10	0
Transfers in	0	(2)	0	(2)
Transfers (out)	0	(2)	0	(2)
Ending balance	16	1	16	1
Total gains (losses) included in earnings	2	0	3	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0		0
Embedded derivatives | Funds withheld at interest
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	763	704	801	57
Total realized and unrealized gains (losses) included in income	496	100	458	747
Total realized and unrealized gains (losses) included in OCI	0	0	0	0
Purchases, issuances, sales and settlements, net	0	0	0	0
Transfers in	0	0	0	0
Ending balance	1,259	804	1,259	804
Total gains (losses) included in earnings	0	0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0		0
Related Party | Investment funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	1,810	141	132	120
Total realized and unrealized gains (losses) included in income	(56)	(1)	113	1
Total realized and unrealized gains (losses) included in OCI	0	0	0	0
Purchases, issuances, sales and settlements, net	16	0	1,525	19
Transfers in	0	0	0	0
Transfers (out)	0		0	0
Ending balance	1,770	140	1,770	140
Total gains (losses) included in earnings	0	1	113	3
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0		0
Related Party | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	52	350	64	133
Total realized and unrealized gains (losses) included in income	0	6	(5)	15
Total realized and unrealized gains (losses) included in OCI	0	0	0	0
Purchases, issuances, sales and settlements, net	(2)	31	(3)	239
Transfers in	0	0	(6)	0
Transfers (out)	0	0	(6)	0
Ending balance	50	387	50	387
Total gains (losses) included in earnings	1	0	(5)	(2)
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0		0
Related Party | Embedded derivatives | Funds withheld at interest
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	560	501	594	(110)
Total realized and unrealized gains (losses) included in income	161	154	127	765
Total realized and unrealized gains (losses) included in OCI	0	0	0	0
Purchases, issuances, sales and settlements, net	0	0	0	0
Transfers in	0	0	0	0
Ending balance	721	655	721	655
Total gains (losses) included in earnings	0	0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0		0
RMBS | AFS securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	16			56
Total realized and unrealized gains (losses) included in income	0			0
Total realized and unrealized gains (losses) included in OCI	2			4
Purchases, issuances, sales and settlements, net	(2)			2
Transfers in	(16)			(62)
Transfers (out)	(16)			(62)
Ending balance	0	0	0	0
Total gains (losses) included in earnings	0			0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0
RMBS | Trading securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	55	46	52	134
Total realized and unrealized gains (losses) included in income	(3)	(5)	(4)	(13)
Total realized and unrealized gains (losses) included in OCI	0	0	0	0
Purchases, issuances, sales and settlements, net	0	15	0	15
Transfers in	7	35	11	(45)
Transfers (out)	(1)	0	(1)	(79)
Ending balance	59	91	59	91
Total gains (losses) included in earnings	0	(2)	5	3
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0		0
ABS | AFS securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	868	1,396	1,374	1,615
Total realized and unrealized gains (losses) included in income	(4)	1	19	6
Total realized and unrealized gains (losses) included in OCI	12	12	(71)	43
Purchases, issuances, sales and settlements, net	(44)	16	(301)	43
Transfers in	147	(137)	(42)	(419)
Transfers (out)	(71)	(137)	(106)	(419)
Ending balance	979	1,288	979	1,288
Total gains (losses) included in earnings	0	0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	13		(69)
ABS | Trading securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	0	6	16	0
Total realized and unrealized gains (losses) included in income	0	0	0	0
Total realized and unrealized gains (losses) included in OCI	0	0	0	0
Purchases, issuances, sales and settlements, net	35	(1)	19	5
Transfers in	0	78	0	78
Transfers (out)	0	0	0	0
Ending balance	35	83	35	83
Total gains (losses) included in earnings	0	0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0		0
ABS | Related Party | AFS securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	2,061	399	2,324	328
Total realized and unrealized gains (losses) included in income	8	0	9	0
Total realized and unrealized gains (losses) included in OCI	25	8	(20)	21
Purchases, issuances, sales and settlements, net	(31)	587	(85)	748
Transfers in	0	0	(165)	(103)
Transfers (out)	0	0	(165)	(103)
Ending balance	2,063	994	2,063	994
Total gains (losses) included in earnings	0	0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	25		(20)
ABS | Related Party | Trading securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	824	218	711	149
Total realized and unrealized gains (losses) included in income	14	4	(13)	(13)
Total realized and unrealized gains (losses) included in OCI	0	0	0	0
Purchases, issuances, sales and settlements, net	507	2	647	(15)
Transfers in	0	0	0	103
Transfers (out)	0	0	0
Ending balance	1,345	224	1,345	224
Total gains (losses) included in earnings	13	5	(14)	(13)
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0		0
CLO | AFS securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	160	200	121	107
Total realized and unrealized gains (losses) included in income	0	0	0	0
Total realized and unrealized gains (losses) included in OCI	2	1	0	3
Purchases, issuances, sales and settlements, net	(7)	34	56	60
Transfers in	36	(104)	14	(39)
Transfers (out)	0	(104)	(22)	(39)
Ending balance	191	131	191	131
Total gains (losses) included in earnings	0	0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	2		0
CLO | Trading securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	3	7	6	1
Total realized and unrealized gains (losses) included in income	0	(1)	(3)	(1)
Total realized and unrealized gains (losses) included in OCI	0	0	0	0
Purchases, issuances, sales and settlements, net	0	0	0	0
Transfers in	0	0	0	6
Transfers (out)				0
Ending balance	3	6	3	6
Total gains (losses) included in earnings	0	0	(1)	6
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0		0
CLO | Related Party | AFS securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	0	37	0
Total realized and unrealized gains (losses) included in income	0	0	0
Total realized and unrealized gains (losses) included in OCI	0	0	0
Purchases, issuances, sales and settlements, net	11	0	11
Transfers in	0	(37)	0
Transfers (out)	0	(37)	0
Ending balance	11	0	11	0
Total gains (losses) included in earnings	0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0		0
CLO | Related Party | Trading securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	45	95	38	113
Total realized and unrealized gains (losses) included in income	3	(5)	(11)	(7)
Total realized and unrealized gains (losses) included in OCI	0	0	0	0
Purchases, issuances, sales and settlements, net	0	(7)	1	(54)
Transfers in	(20)	(23)	0	8
Transfers (out)	(24)	(23)	0	(35)
Ending balance	28	60	28	60
Total gains (losses) included in earnings	3	0	(11)	2
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0		0
Corporate | AFS securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	874	821	725	898
Total realized and unrealized gains (losses) included in income	(26)	(3)	1	(2)
Total realized and unrealized gains (losses) included in OCI	62	10	(1)	20
Purchases, issuances, sales and settlements, net	39	189	118	164
Transfers in	(49)	(70)	57	(133)
Transfers (out)	(206)	(71)	(40)	(134)
Ending balance	900	947	900	947
Total gains (losses) included in earnings	0	0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	75		(1)
Corporate | Trading securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	6	6	0
Total realized and unrealized gains (losses) included in income	0	0	0
Total realized and unrealized gains (losses) included in OCI	0	0	0
Purchases, issuances, sales and settlements, net	0	0	0
Transfers in	0	(6)	6
Transfers (out)		(6)	0
Ending balance	6	0	6	0
Total gains (losses) included in earnings	0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0		0
Corporate | Related Party | AFS securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	0		0
Total realized and unrealized gains (losses) included in income	1		1
Total realized and unrealized gains (losses) included in OCI	2		2
Purchases, issuances, sales and settlements, net	761		761
Transfers in	0		0
Transfers (out)	0		0
Ending balance	764		764
Total gains (losses) included in earnings	0		0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	2		2
CMBS | AFS securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	49	206	46	187
Total realized and unrealized gains (losses) included in income	0	0	(5)	1
Total realized and unrealized gains (losses) included in OCI	5	3	(5)	7
Purchases, issuances, sales and settlements, net	0	195	(5)	154
Transfers in	16	(73)	39	(18)
Transfers (out)	(23)	(73)	0	(18)
Ending balance	70	331	70	331
Total gains (losses) included in earnings	0	0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	5		(5)
Foreign governments | AFS securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	0		0
Total realized and unrealized gains (losses) included in income	0		0
Total realized and unrealized gains (losses) included in OCI	0		0
Purchases, issuances, sales and settlements, net	1		1
Transfers in	0		0
Transfers (out)	0		0
Ending balance	1		1
Total gains (losses) included in earnings	0		0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0		0
U.S. state, municipal and political subdivisions | AFS securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	40	40	40	0
Total realized and unrealized gains (losses) included in income	0	0	0	0
Total realized and unrealized gains (losses) included in OCI	(1)	0	0	0
Purchases, issuances, sales and settlements, net	(5)	0	(6)	40
Transfers in	0	0	0	0
Transfers (out)	0		0	0
Ending balance	34	40	34	40
Total gains (losses) included in earnings	0	0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	(1)		0
Derivative Financial Instruments, Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	(5)	(4)	(3)	(4)
Total realized and unrealized gains (losses) included in income	0	0	(2)	0
Total realized and unrealized gains (losses) included in OCI	0	0	0	0
Purchases, issuances, sales and settlements, net	0	0	0	0
Transfers in	0	0	0	0
Ending balance	(5)	(4)	(5)	(4)
Total gains (losses) included in earnings	0	0	(2)	0
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0		0
Interest sensitive contract liabilities | Embedded derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	(11,140)	(9,905)	(10,942)	(7,969)
Total realized and unrealized gains (losses) included in income	(553)	(265)	(910)	(1,920)
Total realized and unrealized gains (losses) included in OCI	0	0	0	0
Purchases, issuances, sales and settlements, net	(48)	(103)	111	(384)
Transfers in	0	0	0	0
Transfers (out)	0	0	0	0
Ending balance	(11,741)	(10,273)	(11,741)	(10,273)
Total gains (losses) included in earnings	0	0	0	0
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0		0
Universal life | Interest sensitive contract liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	(1,323)	(1,051)	(1,050)	(932)
Total realized and unrealized gains (losses) included in income	(40)	(91)	(313)	(210)
Total realized and unrealized gains (losses) included in OCI	0	0	0	0
Purchases, issuances, sales and settlements, net	0	0	0	0
Transfers in	0	0	0	0
Ending balance	(1,363)	(1,142)	(1,363)	(1,142)
Total gains (losses) included in earnings	0	0	0	0
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0		0
AmerUs Closed Block | Future policy benefits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	(1,573)	(1,535)	(1,546)	(1,443)
Total realized and unrealized gains (losses) included in income	(4)	(37)	(31)	(129)
Total realized and unrealized gains (losses) included in OCI	0	0	0	0
Purchases, issuances, sales and settlements, net	0	0	0	0
Transfers in	0	0	0	0
Ending balance	(1,577)	(1,572)	(1,577)	(1,572)
Total gains (losses) included in earnings	0	0	0	0
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0		0
ILICO Closed Block and life benefits | Future policy benefits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	(761)	(769)	(755)	(730)
Total realized and unrealized gains (losses) included in income	(16)	(28)	(22)	(67)
Total realized and unrealized gains (losses) included in OCI	0	0	0	0
Purchases, issuances, sales and settlements, net	0	0	0	0
Transfers in	0	0	0	0
Ending balance	(777)	(797)	(777)	(797)
Total gains (losses) included in earnings	0	$ 0	0	$ 0
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	$ 0		$ 0