Fair Value - Reconciliation of Level 3 Financial Instruments (Details) - Consolidated Entity Excluding Variable Interest Entities (VIE) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 4,474	$ 4,698	$ 4,164	$ 6,804
Total realized and unrealized gains (losses) included in income	30	61	277	(285)
Total realized and unrealized gains (losses), Included in OCI	14	29	36	76
Purchases, (Sales), Issuances, (Settlements)	215	28	377	(991)
Transfer In	291	19	389	201
Transfers (Out)	(190)	(499)	(409)	(1,469)
Ending Balance	4,834	4,336	4,834	4,336
Total gains (losses) included in earnings	1	10	1	35
Beginning Balance	(9,600)	(8,379)	(8,573)	(8,413)
Total realized and unrealized gains (losses), Included in income	(341)	(251)	(1,177)	(21)
Total realized and unrealized gains (losses), Included in OCI	0	0	0	0
Purchases, (Sales), Issuances, (Settlements), Liabilities	(101)	(209)	(292)	(405)
Transfers In	0	0	0	0
Transfers (Out)	0	0	0	0
Ending Balance	(10,042)	(8,839)	(10,042)	(8,839)
Total gains (losses) included in earnings	0	0	1	0
AFS securities | Equity Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	6	10	5	9
Total realized and unrealized gains (losses) included in income	(1)	0	(1)	0
Total realized and unrealized gains (losses), Included in OCI	0	(1)	1	0
Purchases, (Sales), Issuances, (Settlements)	0	(4)	0	(4)
Transfer In	0	0	0	0
Transfers (Out)	0	0	0	0
Ending Balance	5	5	5	5
Total gains (losses) included in earnings	0	0	0	0
AFS securities | U.S. state, municipal and political subdivisions | Fixed Maturity Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance			5
Total realized and unrealized gains (losses) included in income			17
Total realized and unrealized gains (losses), Included in OCI			(1)
Purchases, (Sales), Issuances, (Settlements)			(21)
Transfer In			0
Transfers (Out)			0
Ending Balance	0		0
Total gains (losses) included in earnings			0
AFS securities | Foreign governments | Fixed Maturity Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	14	16	14	17
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	(1)
Purchases, (Sales), Issuances, (Settlements)	0	(1)	0	(2)
Transfer In	0	0	0	0
Transfers (Out)	(14)	0	(14)	0
Ending Balance	0	15	0	15
Total gains (losses) included in earnings	0	0	0	0
AFS securities | Corporate | Fixed Maturity Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	452	402	370	636
Total realized and unrealized gains (losses) included in income	5	1	10	4
Total realized and unrealized gains (losses), Included in OCI	0	1	10	27
Purchases, (Sales), Issuances, (Settlements)	(13)	24	107	(71)
Transfer In	37	3	23	4
Transfers (Out)	(12)	(89)	(51)	(258)
Ending Balance	469	342	469	342
Total gains (losses) included in earnings	0	0	0	0
AFS securities | CLO | Fixed Maturity Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	81	285	158	517
Total realized and unrealized gains (losses) included in income	0	1	1	3
Total realized and unrealized gains (losses), Included in OCI	1	15	9	38
Purchases, (Sales), Issuances, (Settlements)	47	4	40	7
Transfer In	86	11	53	10
Transfers (Out)	(19)	(193)	(65)	(452)
Ending Balance	196	123	196	123
Total gains (losses) included in earnings	0	0	0	0
AFS securities | CLO | Fixed Maturity Securities | Related Party
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	0	0	0	7
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, (Sales), Issuances, (Settlements)	10	0	10	0
Transfer In	0	0	0	0
Transfers (Out)	0	0	0	(7)
Ending Balance	10	0	10	0
Total gains (losses) included in earnings	0	0	0	0
AFS securities | ABS | Fixed Maturity Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	1,093	1,238	1,160	1,813
Total realized and unrealized gains (losses) included in income	3	3	11	78
Total realized and unrealized gains (losses), Included in OCI	1	11	18	(7)
Purchases, (Sales), Issuances, (Settlements)	240	30	237	(755)
Transfer In	83	0	6	103
Transfers (Out)	(41)	(188)	(53)	(138)
Ending Balance	1,379	1,094	1,379	1,094
Total gains (losses) included in earnings	0	0	0	0
AFS securities | ABS | Fixed Maturity Securities | Related Party
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance		58	56	60
Total realized and unrealized gains (losses) included in income		0	0	0
Total realized and unrealized gains (losses), Included in OCI		0	2	0
Purchases, (Sales), Issuances, (Settlements)		(1)	(5)	(3)
Transfer In		0	0	0
Transfers (Out)		0	(53)	0
Ending Balance	0	57	0	57
Total gains (losses) included in earnings		0	0	0
AFS securities | CMBS | Fixed Maturity Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	122	80	152	67
Total realized and unrealized gains (losses) included in income	1	0	1	1
Total realized and unrealized gains (losses), Included in OCI	(1)	3	(4)	3
Purchases, (Sales), Issuances, (Settlements)	(18)	4	28	10
Transfer In	26	0	0	53
Transfers (Out)	(43)	0	(90)	(47)
Ending Balance	87	87	87	87
Total gains (losses) included in earnings	0	0	0	0
AFS securities | RMBS | Fixed Maturity Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	312	0	17	758
Total realized and unrealized gains (losses) included in income	1	0	1	3
Total realized and unrealized gains (losses), Included in OCI	13	0	1	16
Purchases, (Sales), Issuances, (Settlements)	(11)	0	12	(249)
Transfer In	14	0	300	0
Transfers (Out)	(7)	0	(9)	(528)
Ending Balance	322	0	322	0
Total gains (losses) included in earnings	0	0	0	0
Trading securities | U.S. state, municipal and political subdivisions | Fixed Maturity Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	17	17	17	17
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, (Sales), Issuances, (Settlements)	0	0	0	0
Transfer In	0	0	0	0
Transfers (Out)	0	0	0	0
Ending Balance	17	17	17	17
Total gains (losses) included in earnings	0	0	0	0
Trading securities | Corporate | Fixed Maturity Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance		1		16
Total realized and unrealized gains (losses) included in income		0		0
Total realized and unrealized gains (losses), Included in OCI		0		0
Purchases, (Sales), Issuances, (Settlements)		0		(4)
Transfer In		0		0
Transfers (Out)		(1)		(12)
Ending Balance		0		0
Total gains (losses) included in earnings		0		5
Trading securities | CLO | Related Party
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Purchases, (Sales), Issuances, (Settlements)	(24)		(52)	17
Trading securities | CLO | Fixed Maturity Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	22	104	43	108
Total realized and unrealized gains (losses) included in income	(4)	(1)	(2)	(4)
Total realized and unrealized gains (losses), Included in OCI	0	0	0	0
Purchases, (Sales), Issuances, (Settlements)	0	(44)	(12)	(45)
Transfer In	11	0	0	0
Transfers (Out)	(8)	0	(8)	0
Ending Balance	21	59	21	59
Total gains (losses) included in earnings	(3)	4	1	8
Trading securities | CLO | Fixed Maturity Securities | Related Party
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	123	211	195	191
Total realized and unrealized gains (losses) included in income	3	0	(3)	(23)
Total realized and unrealized gains (losses), Included in OCI	0	0	0	0
Purchases, (Sales), Issuances, (Settlements)	(24)	0	(52)	17
Transfer In	19	0	0	26
Transfers (Out)	(30)	(22)	(49)	(22)
Ending Balance	91	189	91	189
Total gains (losses) included in earnings	2	7	(1)	21
Trading securities | ABS | Fixed Maturity Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance		89		98
Total realized and unrealized gains (losses) included in income		(2)		(11)
Total realized and unrealized gains (losses), Included in OCI		0		0
Purchases, (Sales), Issuances, (Settlements)		0		0
Transfer In		0		0
Transfers (Out)		0		0
Ending Balance		87		87
Total gains (losses) included in earnings		0		0
Trading securities | RMBS | Fixed Maturity Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	100	122	96	29
Total realized and unrealized gains (losses) included in income	(2)	(4)	(11)	(7)
Total realized and unrealized gains (losses), Included in OCI	0	0	0	0
Purchases, (Sales), Issuances, (Settlements)	4	16	26	111
Transfer In	15	0	7	0
Transfers (Out)	(16)	(6)	(17)	(5)
Ending Balance	101	128	101	128
Total gains (losses) included in earnings	3	(1)	2	1
Mortgage loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	43	45	44	48
Total realized and unrealized gains (losses) included in income	(1)	0	(1)	0
Total realized and unrealized gains (losses), Included in OCI	0	0	0	0
Purchases, (Sales), Issuances, (Settlements)	0	0	(1)	(3)
Transfer In	0	0	0	0
Transfers (Out)	0	0	0	0
Ending Balance	42	45	42	45
Total gains (losses) included in earnings	(1)	0	(1)	0
Short-term Investments | Related Party
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	28		0
Total realized and unrealized gains (losses) included in income	0		0
Total realized and unrealized gains (losses), Included in OCI	0		0
Purchases, (Sales), Issuances, (Settlements)	(20)		8
Transfer In	0		0
Transfers (Out)	0		0
Ending Balance	8		8
Total gains (losses) included in earnings	0		0
Reinsurance recoverable
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	1,782	1,898	1,692	2,377
Total realized and unrealized gains (losses) included in income	1	(20)	91	(499)
Total realized and unrealized gains (losses), Included in OCI	0	0	0	0
Purchases, (Sales), Issuances, (Settlements)	0	0	0	0
Transfer In	0	0	0	0
Transfers (Out)	0	0	0	0
Ending Balance	1,783	1,878	1,783	1,878
Total gains (losses) included in earnings	0	0	0	0
Embedded derivatives | Funds withheld at interest
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	279	122	140	36
Total realized and unrealized gains (losses) included in income	24	83	163	169
Total realized and unrealized gains (losses), Included in OCI	0	0	0	0
Purchases, (Sales), Issuances, (Settlements)	0	0	0	0
Transfer In	0	0	0	0
Transfers (Out)	0	0	0	0
Ending Balance	303	205	303	205
Total gains (losses) included in earnings	0	0	0	0
Interest sensitive contract liabilities | Universal life
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	(954)	(1,059)	(883)	(1,464)
Total realized and unrealized gains (losses), Included in income	(3)	9	(74)	414
Total realized and unrealized gains (losses), Included in OCI	0	0	0	0
Purchases, (Sales), Issuances, (Settlements), Liabilities	0	0	0	0
Transfers In	0	0	0	0
Transfers (Out)	0	0	0	0
Ending Balance	(957)	(1,050)	(957)	(1,050)
Total gains (losses) included in earnings	0	0	0	0
Interest sensitive contract liabilities | Embedded derivatives
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	(6,207)	(4,807)	(5,283)	(4,464)
Total realized and unrealized gains (losses), Included in income	(344)	(243)	(1,077)	(390)
Total realized and unrealized gains (losses), Included in OCI	0	0	0	0
Purchases, (Sales), Issuances, (Settlements), Liabilities	(101)	(209)	(292)	(405)
Transfers In	0	0	0	0
Transfers (Out)	0	0	0	0
Ending Balance	(6,652)	(5,259)	(6,652)	(5,259)
Total gains (losses) included in earnings	0	0	0	0
Future policy benefits | AmerUs Closed Block
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	(1,621)	(1,682)	(1,606)	(1,581)
Total realized and unrealized gains (losses), Included in income	5	(28)	(10)	(129)
Total realized and unrealized gains (losses), Included in OCI	0	0	0	0
Purchases, (Sales), Issuances, (Settlements), Liabilities	0	0	0	0
Transfers In	0	0	0	0
Transfers (Out)	0	0	0	0
Ending Balance	(1,616)	(1,710)	(1,616)	(1,710)
Total gains (losses) included in earnings	0	0	0	0
Future policy benefits | ILICO Closed Block and life benefits
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	(812)	(823)	(794)	(897)
Total realized and unrealized gains (losses), Included in income	1	11	(17)	85
Total realized and unrealized gains (losses), Included in OCI	0	0	0	0
Purchases, (Sales), Issuances, (Settlements), Liabilities	0	0	0	0
Transfers In	0	0	0	0
Transfers (Out)	0	0	0	0
Ending Balance	(811)	(812)	(811)	(812)
Total gains (losses) included in earnings	0	0	0	0
Derivative liabilities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	(6)	(8)	(7)	(7)
Total realized and unrealized gains (losses), Included in income	0	0	1	(1)
Total realized and unrealized gains (losses), Included in OCI	0	0	0	0
Purchases, (Sales), Issuances, (Settlements), Liabilities	0	0	0	0
Transfers In	0	0	0	0
Transfers (Out)	0	0	0	0
Ending Balance	(6)	(8)	(6)	(8)
Total gains (losses) included in earnings	$ 0	$ 0	$ 1	$ 0