Fair Value (Unobservable Input Reconciliation) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Residential mortgage loans - FVO
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	$ 119	$ 149	$ 127	$ 165
Total realized/unrealized gains (losses) included in net income (loss)	(5)	(1)	(9)	(3)
Total realized/unrealized gains (losses) included in AOCI	0	0	0	0
Purchases	0	0	0	0
Sales	0	(2)	0	(11)
Issuances	0	0	0	0
Settlements	(5)	(6)	(9)	(11)
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Balance, end of period	109	140	109	140
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	(5)	(2)	(9)	(7)
Changes in unrealized gains (losses) included in AOCI 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	(5)	(2)	(9)	(7)
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	0	0	0	0
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	(291)	(69)	(15)	(132)
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	(199)	200	(390)	(274)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance, beginning of period	31	(162)	(152)	594
Total realized/unrealized gains (losses) included in net income (loss)	(292)	(49)	17	(217)
Total realized/unrealized gains (losses) included in AOCI	(191)	205	(410)	(412)
Purchases	152	4	240	4
Sales	0	0	0	0
Issuances	0	(5)	(2)	(6)
Settlements	13	0	20	94
Transfers into Level 3	0	0	0	1
Transfers out of Level 3	0	64	0	(1)
Balance, end of period	(287)	57	(287)	57
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	(291)	(69)	(15)	(132)
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	(199)	200	(390)	(274)
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	97	(3)	139	668
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	13	1	22	22
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance, beginning of period	(578)	(508)	(611)	(1,141)
Total realized/unrealized gains (losses) included in net income (loss)	97	(4)	139	669
Total realized/unrealized gains (losses) included in AOCI	14	1	23	22
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	(29)	(63)	(47)	(124)
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Balance, end of period	(496)	(574)	(496)	(574)
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	97	(3)	139	668
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	13	1	22	22
Corporate fixed maturity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	24,362	23,419	25,435	24,101
Total realized/unrealized gains (losses) included in net income (loss)	(5)	(8)	(16)	(5)
Total realized/unrealized gains (losses) included in AOCI	(2,857)	415	(4,892)	(776)
Purchases	1,643	868	2,698	1,722
Sales	(315)	(286)	(782)	(507)
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers into Level 3	154	48	463	101
Transfers out of Level 3	(400)	(683)	(324)	(863)
Balance, end of period	22,582	23,773	22,582	23,773
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	(5)	(8)	(16)	(8)
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	(2,851)	416	(4,885)	(767)
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	(5)	(8)	(16)	(8)
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	(2,851)	416	(4,885)	(767)
Foreign government
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	248	132	91	117
Total realized/unrealized gains (losses) included in net income (loss)	4	0	(43)	1
Total realized/unrealized gains (losses) included in AOCI	3	0	7	(1)
Purchases	1	46	1	46
Sales	(2)	(3)	(2)	(5)
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers into Level 3	3	10	49	13
Transfers out of Level 3	(154)	(40)	0	(26)
Balance, end of period	103	145	103	145
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	4	0	(43)	1
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	3	0	6	(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	4	0	(43)	1
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	3	0	6	(1)
Structured Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	5,930	5,507	5,871	5,289
Total realized/unrealized gains (losses) included in net income (loss)	12	16	23	24
Total realized/unrealized gains (losses) included in AOCI	(207)	19	(423)	(28)
Purchases	536	823	732	1,380
Sales	(468)	(332)	(668)	(685)
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers into Level 3	129	345	190	270
Transfers out of Level 3	(585)	(375)	(378)	(247)
Balance, end of period	5,347	6,003	5,347	6,003
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	12	15	23	22
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	(205)	19	(416)	(26)
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	12	15	23	22
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	(205)	19	(416)	(26)
Municipals
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	29	5	0	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	0	0	0	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	(29)	(5)	0	0
Balance, end of period	0	0	0	0
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	0	0	0	0
Changes in unrealized gains (losses) included in AOCI 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
Changes in unrealized gains (losses) included in AOCI 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	189	154	151	150
Total realized/unrealized gains (losses) included in net income (loss)	(2)	6	11	10
Total realized/unrealized gains (losses) included in AOCI	0	0	0	0
Purchases	2	3	25	3
Sales	(10)	(15)	(6)	(16)
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	(5)	(2)	(4)
Balance, end of period	179	143	179	143
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	(3)	3	9	5
Changes in unrealized gains (losses) included in AOCI 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	(3)	3	9	5
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	0	0	0	0
Unit-linked and FVO Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	868	812	901	701
Total realized/unrealized gains (losses) included in net income (loss)	(132)	45	(169)	62
Total realized/unrealized gains (losses) included in AOCI	0	0	0	0
Purchases	8	12	15	21
Sales	(2)	(16)	(4)	(15)
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers into Level 3	0	10	13	95
Transfers out of Level 3	0	(14)	(14)	(15)
Balance, end of period	742	849	742	849
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	(132)	44	(168)	61
Changes in unrealized gains (losses) included in AOCI 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	(132)	44	(168)	61
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	0	0	0	0
Short-term Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	5	102	3	43
Total realized/unrealized gains (losses) included in net income (loss)	0	0	(1)	0
Total realized/unrealized gains (losses) included in AOCI	0	1	0	(1)
Purchases	15	35	119	84
Sales	(1)	(46)	(2)	(10)
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers into Level 3	100	50	0	0
Transfers out of Level 3	0	(29)	0	(3)
Balance, end of period	119	113	119	113
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	0	0	0	0
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	0	(1)	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	0	0	0	0
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	0	(1)	0	(1)
Short-term Investments | MetLife Poland and Greece
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Transfers out of Level 3		(28)
Other Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	1,047	656	898	573
Total realized/unrealized gains (losses) included in net income (loss)	26	12	72	25
Total realized/unrealized gains (losses) included in AOCI	0	0	0	0
Purchases	61	113	187	183
Sales	(21)	0	(44)	0
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	(100)	0	(100)	0
Balance, end of period	1,013	781	1,013	781
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	23	12	69	26
Changes in unrealized gains (losses) included in AOCI 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	23	12	69	26
Changes in unrealized gains (losses) included in AOCI 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	2,118	1,133	2,131	1,079
Total realized/unrealized gains (losses) included in net income (loss)	24	12	43	2
Total realized/unrealized gains (losses) included in AOCI	0	0	0	0
Purchases	36	118	107	188
Sales	(949)	(27)	(1,047)	(32)
Issuances	(5)	1	(5)	0
Settlements	6	3	4	5
Transfers into Level 3	0	9	1	10
Transfers out of Level 3	0	0	(4)	(3)
Balance, end of period	1,230	1,249	1,230	1,249
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	0	0	0	0
Changes in unrealized gains (losses) included in AOCI 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
Changes in unrealized gains (losses) included in AOCI for the instruments still held at end of period	$ 0	$ 0	$ 0	$ 0