Fair Value (Unobservable Input Reconciliation) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Residential mortgage loans - FVO
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at January 1,	$ 299	$ 520
Total realized/unrealized gains (losses) included in net income (loss)	7	7	$ 40
Total realized/unrealized gains (losses) included in AOCI	0	0	0
Purchases	0	0
Sales	(87)	(162)
Issuances	0	0
Settlements	(31)	(66)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Balance at December 31,	188	299	520
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	(14)	(15)	27
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	(14)	(15)	27
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	(129)	(59)	53
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance at January 1,	(225)	(132)
Total realized/unrealized gains (losses) included in net income (loss)	(108)	(161)	87
Total realized/unrealized gains (losses) included in AOCI	157	(140)	216
Purchases	4	5
Sales	0	0
Issuances	(2)	(1)
Settlements	29	204
Transfers into Level 3	(1)	0
Transfers out of Level 3	0	0
Balance at December 31,	(146)	(225)	(132)
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	(129)	(59)	53
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	264	(150)	793
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance at January 1,	(739)	(274)
Total realized/unrealized gains (losses) included in net income (loss)	274	(150)	823
Total realized/unrealized gains (losses) included in AOCI	(2)	(15)	(46)
Purchases	0	0
Sales	0	0
Issuances	0	0
Settlements	(275)	(300)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Balance at December 31,	(742)	(739)	(274)
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	264	(150)	793
Corporate fixed maturity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at January 1,	10,467	11,219
Total realized/unrealized gains (losses) included in net income (loss)	(49)	9	3
Total realized/unrealized gains (losses) included in AOCI	893	(745)	708
Purchases	3,689	1,903
Sales	(870)	(1,464)
Issuances	0	0
Settlements	0	0
Transfers into Level 3	606	152
Transfers out of Level 3	(507)	(607)
Balance at December 31,	14,229	10,467	11,219
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	(50)	1	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	(50)	1	1
Foreign government
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at January 1,	138	209
Total realized/unrealized gains (losses) included in net income (loss)	0	3	4
Total realized/unrealized gains (losses) included in AOCI	(2)	(14)	0
Purchases	10	5
Sales	(24)	(47)
Issuances	0	0
Settlements	0	0
Transfers into Level 3	20	0
Transfers out of Level 3	(25)	(18)
Balance at December 31,	117	138	209
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	0	1	4
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	1	4
Structured Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at January 1,	4,266	4,841
Total realized/unrealized gains (losses) included in net income (loss)	46	82	94
Total realized/unrealized gains (losses) included in AOCI	42	(23)	133
Purchases	1,338	1,142
Sales	(737)	(946)
Issuances	0	0
Settlements	0	0
Transfers into Level 3	0	59
Transfers out of Level 3	(497)	(889)
Balance at December 31,	4,458	4,266	4,841
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	44	70	84
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	44	70	84
Municipals
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at January 1,	0	0
Total realized/unrealized gains (losses) included in net income (loss)	0	0	0
Total realized/unrealized gains (losses) included in AOCI	0	0	0
Purchases	7	0
Sales	0	0
Issuances	0	0
Settlements	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Balance at December 31,	7	0	0
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	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
Equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at January 1,	419	428
Total realized/unrealized gains (losses) included in net income (loss)	47	(36)	0
Total realized/unrealized gains (losses) included in AOCI	0	0	19
Purchases	65	13
Sales	(98)	(28)
Issuances	0	0
Settlements	0	0
Transfers into Level 3	0	52
Transfers out of Level 3	(3)	(10)
Balance at December 31,	430	419	428
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	39	(26)	(17)
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	39	(26)	(17)
Unit-linked and FVO Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at January 1,	405	362
Total realized/unrealized gains (losses) included in net income (loss)	48	6	22
Total realized/unrealized gains (losses) included in AOCI	0	0	0
Purchases	203	263
Sales	(39)	(176)
Issuances	0	0
Settlements	0	0
Transfers into Level 3	20	9
Transfers out of Level 3	(12)	(59)
Balance at December 31,	625	405	362
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	48	8	19
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	48	8	19
Short-term Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at January 1,	33	33
Total realized/unrealized gains (losses) included in net income (loss)	0	(1)	0
Total realized/unrealized gains (losses) included in AOCI	(1)	(1)	0
Purchases	31	34
Sales	(33)	(12)
Issuances	0	0
Settlements	0	0
Transfers into Level 3	2	0
Transfers out of Level 3	0	(20)
Balance at December 31,	32	33	33
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	0	(1)	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	(1)	0
Other Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at January 1,	39	0
Total realized/unrealized gains (losses) included in net income (loss)	0	0	0
Total realized/unrealized gains (losses) included in AOCI	0	0	0
Purchases	416	39
Sales	0	0
Issuances	0	0
Settlements	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Balance at December 31,	455	39	0
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	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
Separate Accounts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at January 1,	937	959
Total realized/unrealized gains (losses) included in net income (loss)	7	7	(8)
Total realized/unrealized gains (losses) included in AOCI	0	0	0
Purchases	191	198
Sales	(151)	(168)
Issuances	(3)	(3)
Settlements	2	(1)
Transfers into Level 3	0	53
Transfers out of Level 3	(3)	(108)
Balance at December 31,	980	937	959
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	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

Amount of unrealized gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3) and still held.

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Amount of gain (loss) recognized in income from derivative asset (liability) after deduction of derivative liability (asset), measured at fair value on recurring basis using unobservable input (level 3).

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Amount of gain (loss) recognized in other comprehensive income from derivative asset (liability) after deduction of derivative liability (asset), measured at fair value on recurring basis using unobservable input (level 3).

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Amount of issuances of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of purchases of financial instrument classified as a derivative asset (liability) after deduction of derivative liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of transfers of financial instrument classified as derivative asset (liability) after deduction of derivative liability (asset) out of level 3 of the fair value hierarchy.

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Fair value of financial instrument classified as derivative asset (liability) after deduction of derivative liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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