Insurance (Liabilities for Guarantees) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Universal and Variable Life Contracts | Secondary Guarantees | Foreign Currency Translation
Movement In Guaranteed Benefit Liability Gross Rollforward
Incurred guaranteed benefits	$ (268)	$ (260)	$ 125
Direct and Assumed
Movement In Guaranteed Benefit Liability Gross Rollforward
Balance at January 1,	6,450	6,441	5,548
Incurred guaranteed benefits	(179)	226	1,063
Paid guaranteed benefits	(217)	(185)	(170)
Liabilities for Guarantees on Long-Duration Contracts, Other Liability Adjustments		(32)
Balance at December 31,	6,054	6,450	6,441
Direct and Assumed | Secondary Guarantees
Movement In Guaranteed Benefit Liability Gross Rollforward
Balance at January 1,	4,126	4,265	3,762
Incurred guaranteed benefits	(261)	(37)	602
Paid guaranteed benefits	(120)	(102)	(99)
Balance at December 31,	3,745	4,126	4,265
Direct and Assumed | Secondary Guarantees | MetLife Poland and Greece
Movement In Guaranteed Benefit Liability Gross Rollforward
Liabilities for Guarantees on Long-Duration Contracts, Other Liability Adjustments		0
Direct and Assumed | Paid-Up Guarantees
Movement In Guaranteed Benefit Liability Gross Rollforward
Balance at January 1,	404	408	427
Incurred guaranteed benefits	104	43	26
Paid guaranteed benefits	(44)	(47)	(45)
Balance at December 31,	464	404	408
Direct and Assumed | Paid-Up Guarantees | MetLife Poland and Greece
Movement In Guaranteed Benefit Liability Gross Rollforward
Liabilities for Guarantees on Long-Duration Contracts, Other Liability Adjustments		0
Direct and Assumed | Guaranteed Minimum Death and Withdrawal Benefit [Member]
Movement In Guaranteed Benefit Liability Gross Rollforward
Balance at January 1,	743	639	465
Incurred guaranteed benefits	247	133	195
Paid guaranteed benefits	(39)	(29)	(21)
Balance at December 31,	951	743	639
Direct and Assumed | Guaranteed Minimum Death and Withdrawal Benefit [Member] | MetLife Poland and Greece
Movement In Guaranteed Benefit Liability Gross Rollforward
Liabilities for Guarantees on Long-Duration Contracts, Other Liability Adjustments		0
Direct and Assumed | Guaranteed Minimum Income Benefit
Movement In Guaranteed Benefit Liability Gross Rollforward
Balance at January 1,	1,177	1,129	894
Incurred guaranteed benefits	(269)	87	240
Paid guaranteed benefits	(14)	(7)	(5)
Balance at December 31,	894	1,177	1,129
Direct and Assumed | Guaranteed Minimum Income Benefit | MetLife Poland and Greece
Movement In Guaranteed Benefit Liability Gross Rollforward
Liabilities for Guarantees on Long-Duration Contracts, Other Liability Adjustments		(32)
Ceded
Movement In Guaranteed Benefit Liability Gross Rollforward
Balance at January 1,	748	724	640
Incurred guaranteed benefits	53	83	125
Paid guaranteed benefits	(48)	(59)	(41)
Liabilities for Guarantees on Long-Duration Contracts, Other Liability Adjustments		0
Balance at December 31,	753	748	724
Ceded | Secondary Guarantees
Movement In Guaranteed Benefit Liability Gross Rollforward
Balance at January 1,	451	427	349
Incurred guaranteed benefits	29	57	96
Paid guaranteed benefits	(24)	(33)	(18)
Balance at December 31,	456	451	427
Ceded | Secondary Guarantees | MetLife Poland and Greece
Movement In Guaranteed Benefit Liability Gross Rollforward
Liabilities for Guarantees on Long-Duration Contracts, Other Liability Adjustments		0
Ceded | Paid-Up Guarantees
Movement In Guaranteed Benefit Liability Gross Rollforward
Balance at January 1,	288	292	281
Incurred guaranteed benefits	33	30	43
Paid guaranteed benefits	(32)	(34)	(32)
Balance at December 31,	289	288	292
Ceded | Paid-Up Guarantees | MetLife Poland and Greece
Movement In Guaranteed Benefit Liability Gross Rollforward
Liabilities for Guarantees on Long-Duration Contracts, Other Liability Adjustments		0
Ceded | Guaranteed Minimum Death and Withdrawal Benefit [Member]
Movement In Guaranteed Benefit Liability Gross Rollforward
Balance at January 1,	0	(2)	0
Incurred guaranteed benefits	(8)	(6)	(11)
Paid guaranteed benefits	8	8	9
Balance at December 31,	0	0	(2)
Ceded | Guaranteed Minimum Death and Withdrawal Benefit [Member] | MetLife Poland and Greece
Movement In Guaranteed Benefit Liability Gross Rollforward
Liabilities for Guarantees on Long-Duration Contracts, Other Liability Adjustments		0
Ceded | Guaranteed Minimum Income Benefit
Movement In Guaranteed Benefit Liability Gross Rollforward
Balance at January 1,	9	7	10
Incurred guaranteed benefits	(1)	2	(3)
Paid guaranteed benefits	0	0	0
Balance at December 31,	8	9	7
Ceded | Guaranteed Minimum Income Benefit | MetLife Poland and Greece
Movement In Guaranteed Benefit Liability Gross Rollforward
Liabilities for Guarantees on Long-Duration Contracts, Other Liability Adjustments		0
Net
Movement In Guaranteed Benefit Liability Gross Rollforward
Balance at January 1,	5,702	5,717	4,908
Incurred guaranteed benefits	(232)	143	938
Paid guaranteed benefits	(169)	(126)	(129)
Liabilities for Guarantees on Long-Duration Contracts, Other Liability Adjustments		(32)
Balance at December 31,	5,301	5,702	5,717
Net | Secondary Guarantees
Movement In Guaranteed Benefit Liability Gross Rollforward
Balance at January 1,	3,675	3,838	3,413
Incurred guaranteed benefits	(290)	(94)	506
Paid guaranteed benefits	(96)	(69)	(81)
Balance at December 31,	3,289	3,675	3,838
Net | Secondary Guarantees | MetLife Poland and Greece
Movement In Guaranteed Benefit Liability Gross Rollforward
Liabilities for Guarantees on Long-Duration Contracts, Other Liability Adjustments		0
Net | Paid-Up Guarantees
Movement In Guaranteed Benefit Liability Gross Rollforward
Balance at January 1,	116	116	146
Incurred guaranteed benefits	71	13	(17)
Paid guaranteed benefits	(12)	(13)	(13)
Balance at December 31,	175	116	116
Net | Paid-Up Guarantees | MetLife Poland and Greece
Movement In Guaranteed Benefit Liability Gross Rollforward
Liabilities for Guarantees on Long-Duration Contracts, Other Liability Adjustments		0
Net | Guaranteed Minimum Death and Withdrawal Benefit [Member]
Movement In Guaranteed Benefit Liability Gross Rollforward
Balance at January 1,	743	641	465
Incurred guaranteed benefits	255	139	206
Paid guaranteed benefits	(47)	(37)	(30)
Balance at December 31,	951	743	641
Net | Guaranteed Minimum Death and Withdrawal Benefit [Member] | MetLife Poland and Greece
Movement In Guaranteed Benefit Liability Gross Rollforward
Liabilities for Guarantees on Long-Duration Contracts, Other Liability Adjustments		0
Net | Guaranteed Minimum Income Benefit
Movement In Guaranteed Benefit Liability Gross Rollforward
Balance at January 1,	1,168	1,122	884
Incurred guaranteed benefits	(268)	85	243
Paid guaranteed benefits	(14)	(7)	(5)
Balance at December 31,	$ 886	1,168	$ 1,122
Net | Guaranteed Minimum Income Benefit | MetLife Poland and Greece
Movement In Guaranteed Benefit Liability Gross Rollforward
Liabilities for Guarantees on Long-Duration Contracts, Other Liability Adjustments		$ (32)