Fair Value (Unobservable Input Reconciliation) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Residential mortgage loans - FVO
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	$ 262	$ 405	$ 299	$ 520
Total realized/unrealized gains (losses) included in net income (loss)	2	4	8	7
Total realized/unrealized gains (losses) included in AOCI	0	0	0	0
Purchases	0	0	0	0
Sales	(39)	(70)	(64)	(151)
Issuances	0	0	0	0
Settlements	(7)	(16)	(25)	(53)
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Balance, end of period	218	323	218	323
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	(8)	(5)	(7)	(13)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	(8)	(5)	(7)	(13)
Net Derivatives
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	(22)	(38)	27	(66)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance, beginning of period	105	(267)	(225)	(132)
Total realized/unrealized gains (losses) included in net income (loss)	27	(70)	48	(151)
Total realized/unrealized gains (losses) included in AOCI	216	(107)	439	(228)
Purchases	0	0	4	4
Sales	0	0	0	0
Issuances	0	0	(1)	0
Settlements	(107)	37	(24)	100
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Balance, end of period	241	(407)	241	(407)
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	(22)	(38)	27	(66)
Net Embedded Derivatives
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	(219)	168	(173)	352
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance, beginning of period	(835)	(240)	(739)	(274)
Total realized/unrealized gains (losses) included in net income (loss)	(218)	167	(170)	355
Total realized/unrealized gains (losses) included in AOCI	1	9	(7)	6
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	(72)	(75)	(208)	(226)
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Balance, end of period	(1,124)	(139)	(1,124)	(139)
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	(219)	168	(173)	352
Corporate fixed maturity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	11,607	10,621	10,467	11,219
Total realized/unrealized gains (losses) included in net income (loss)	(12)	2	(6)	13
Total realized/unrealized gains (losses) included in AOCI	111	(176)	717	(621)
Purchases	922	594	2,073	1,606
Sales	(260)	(497)	(618)	(1,366)
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers into Level 3	605	84	601	88
Transfers out of Level 3	(79)	(295)	(340)	(606)
Balance, end of period	12,894	10,333	12,894	10,333
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	(6)	2	(10)	3
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	(6)	2	(10)	3
Foreign government
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	143	156	138	209
Total realized/unrealized gains (losses) included in net income (loss)	(1)	0	0	1
Total realized/unrealized gains (losses) included in AOCI	(5)	(4)	(6)	(16)
Purchases	0	4	4	5
Sales	(1)	(6)	(6)	(21)
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers into Level 3	2	5	12	0
Transfers out of Level 3	(1)	(15)	(5)	(38)
Balance, end of period	137	140	137	140
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	(1)	0	0	1
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	(1)	0	0	1
Structured Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	4,155	4,677	4,266	4,841
Total realized/unrealized gains (losses) included in net income (loss)	11	30	36	73
Total realized/unrealized gains (losses) included in AOCI	5	(15)	65	1
Purchases	525	746	948	919
Sales	(179)	(281)	(508)	(788)
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers into Level 3	0	36	2	50
Transfers out of Level 3	(170)	(977)	(462)	(880)
Balance, end of period	4,347	4,216	4,347	4,216
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	10	27	35	66
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	10	27	35	66
US States and Political Subdivisions Debt Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	7	8	0	0
Total realized/unrealized gains (losses) included in net income (loss)	0	0	0	0
Total realized/unrealized gains (losses) included in AOCI	1	0	1	0
Purchases	0	0	7	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	(8)	0	0
Balance, end of period	8	0	8	0
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	0	0	0	0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	0	0	0	0
Equity Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	457	408	419	428
Total realized/unrealized gains (losses) included in net income (loss)	1	(1)	29	(11)
Total realized/unrealized gains (losses) included in AOCI	0	0	0	0
Purchases	1	6	49	11
Sales	(22)	(7)	(60)	(20)
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers into Level 3	0	45	0	45
Transfers out of Level 3	0	(8)	0	(10)
Balance, end of period	437	443	437	443
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	1	0	21	0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	1	0	21	0
Unit-linked and FVO Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	494	269	405	362
Total realized/unrealized gains (losses) included in net income (loss)	(2)	(2)	21	(7)
Total realized/unrealized gains (losses) included in AOCI	0	0	0	0
Purchases	74	48	117	77
Sales	(65)	(32)	(41)	(162)
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers into Level 3	0	12	3	10
Transfers out of Level 3	(2)	(69)	(6)	(54)
Balance, end of period	499	226	499	226
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	(6)	(2)	17	(8)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	(6)	(2)	17	(8)
Short-term Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	123	559	33	33
Total realized/unrealized gains (losses) included in net income (loss)	0	0	0	0
Total realized/unrealized gains (losses) included in AOCI	(1)	(3)	(2)	(7)
Purchases	255	102	372	659
Sales	(3)	(2)	(31)	(11)
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers into Level 3	0	0	2	0
Transfers out of Level 3	0	(2)	0	(20)
Balance, end of period	374	654	374	654
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	0	0	0	0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	0	0	0	0
Other Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	232	0	39	0
Total realized/unrealized gains (losses) included in net income (loss)	0	0	0	0
Total realized/unrealized gains (losses) included in AOCI	0	0	0	0
Purchases	91	0	284	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Balance, end of period	323	0	323	0
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	0	0	0	0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	0	0	0	0
Separate Accounts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	925	1,138	937	959
Total realized/unrealized gains (losses) included in net income (loss)	5	2	10	2
Total realized/unrealized gains (losses) included in AOCI	0	0	0	0
Purchases	107	148	147	200
Sales	(88)	(215)	(146)	(162)
Issuances	0	0	2	(3)
Settlements	(2)	0	(3)	0
Transfers into Level 3	0	5	0	81
Transfers out of Level 3	0	(77)	0	(76)
Balance, end of period	947	1,001	947	1,001
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	0	0	0	0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	$ 0	$ 0	$ 0	$ 0