Deferred Policy Acquisition Costs, Value of Business Acquired and Other Policy-Related Intangibles (DAC and VOBA) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Jan. 01, 2021
Deferred Policy Acquisition Costs and Present Value of Future Insurance Profits, Net [Abstract]
Balance at December 31, 2020	$ 17,644	$ 17,415	$ 13,446
Capitalization of DAC	2,917	2,614	2,751
Amortization	1,791	1,655	1,806
Effect of foreign currency translation and other of DAC	(382)	(730)	(878)
Reclassified to assets held-for-sale (1)			(103)
Balance at January 1, 2021	18,388	17,644	17,415
Balance at December 31, 2020	2,009	2,391	2,943
Total amortization of VOBA	(161)	(176)	(231)
Effect of foreign currency translation and other of VOBA	(85)	(206)	(310)
Reclassified to assets held-for-sale			(34)
Balance at January 1, 2021	1,763	2,009	2,391
Deferred Policy Acquisition Costs and Present Value of Future Insurance Profits, Net, Ending Balance	20,151	19,653	19,806
Deferred Policy Acquisition Cost and Present Value of Future Profit [Line Items]
Deferred Policy Acquisition Cost	18,388	17,644	17,415	$ 17,451
Capitalization of DAC	2,917	2,614	2,751
Deferred Policy Acquisition Costs, Amortization Expense	(1,791)	(1,655)	(1,806)
Effect of foreign currency translation and other of DAC	(382)	(730)	(878)
Reclassified to assets held-for-sale (1)			103
Present Value of Future Insurance Profits, Net	1,763	2,009	2,391	2,966
Total amortization of VOBA	(161)	(176)	(231)
Effect of foreign currency translation and other of VOBA	(85)	(206)	(310)
Reclassified to assets held-for-sale			(34)
Deferred policy acquisition costs and value of business acquired	20,151	19,653	19,806	20,417
Group Benefits
Deferred Policy Acquisition Costs and Present Value of Future Insurance Profits, Net [Abstract]
Balance at December 31, 2020	264	272	279
Capitalization of DAC	20	18	19
Amortization	26	26	26
Effect of foreign currency translation and other of DAC	0	0	0
Reclassified to assets held-for-sale (1)			0
Balance at January 1, 2021	258	264	272
Balance at December 31, 2020	0	0	0
Total amortization of VOBA	0	0	0
Effect of foreign currency translation and other of VOBA	0	0	0
Reclassified to assets held-for-sale			0
Balance at January 1, 2021	0	0	0
Deferred Policy Acquisition Costs and Present Value of Future Insurance Profits, Net, Ending Balance	258	264
Deferred Policy Acquisition Cost and Present Value of Future Profit [Line Items]
Deferred Policy Acquisition Cost	258	264	272	279
Capitalization of DAC	20	18	19
Deferred Policy Acquisition Costs, Amortization Expense	(26)	(26)	(26)
Effect of foreign currency translation and other of DAC	0	0	0
Reclassified to assets held-for-sale (1)			0
Present Value of Future Insurance Profits, Net	0	0	0	0
Total amortization of VOBA	0	0	0
Effect of foreign currency translation and other of VOBA	0	0	0
Reclassified to assets held-for-sale			0
Deferred policy acquisition costs and value of business acquired	258	264
Retirement and Income Solutions
Deferred Policy Acquisition Costs and Present Value of Future Insurance Profits, Net [Abstract]
Balance at December 31, 2020	267	191	130
Capitalization of DAC	176	113	95
Amortization	46	37	34
Effect of foreign currency translation and other of DAC	0	0	0
Reclassified to assets held-for-sale (1)			0
Balance at January 1, 2021	397	267	191
Balance at December 31, 2020	19	22	25
Total amortization of VOBA	(3)	(3)	(3)
Effect of foreign currency translation and other of VOBA	0	0	0
Reclassified to assets held-for-sale			0
Balance at January 1, 2021	16	19	22
Deferred Policy Acquisition Costs and Present Value of Future Insurance Profits, Net, Ending Balance	413	286
Deferred Policy Acquisition Cost and Present Value of Future Profit [Line Items]
Deferred Policy Acquisition Cost	397	267	191	130
Capitalization of DAC	176	113	95
Deferred Policy Acquisition Costs, Amortization Expense	(46)	(37)	(34)
Effect of foreign currency translation and other of DAC	0	0	0
Reclassified to assets held-for-sale (1)			0
Present Value of Future Insurance Profits, Net	16	19	22	25
Total amortization of VOBA	(3)	(3)	(3)
Effect of foreign currency translation and other of VOBA	0	0	0
Reclassified to assets held-for-sale			0
Deferred policy acquisition costs and value of business acquired	413	286
Asia
Deferred Policy Acquisition Costs and Present Value of Future Insurance Profits, Net [Abstract]
Balance at December 31, 2020	10,270	10,058	7,432
Capitalization of DAC	1,583	1,530	1,601
Amortization	705	644	655
Effect of foreign currency translation and other of DAC	(284)	(674)	(629)
Reclassified to assets held-for-sale (1)			0
Balance at January 1, 2021	10,864	10,270	10,058
Balance at December 31, 2020	1,290	1,593	1,901
Total amortization of VOBA	(89)	(101)	(131)
Effect of foreign currency translation and other of VOBA	(82)	(202)	(191)
Reclassified to assets held-for-sale			0
Balance at January 1, 2021	1,119	1,290	1,593
Deferred Policy Acquisition Costs and Present Value of Future Insurance Profits, Net, Ending Balance	11,983	11,560
Deferred Policy Acquisition Cost and Present Value of Future Profit [Line Items]
Deferred Policy Acquisition Cost	10,864	10,270	10,058	9,741
Capitalization of DAC	1,583	1,530	1,601
Deferred Policy Acquisition Costs, Amortization Expense	(705)	(644)	(655)
Effect of foreign currency translation and other of DAC	(284)	(674)	(629)
Reclassified to assets held-for-sale (1)			0
Present Value of Future Insurance Profits, Net	1,119	1,290	1,593	1,915
Total amortization of VOBA	(89)	(101)	(131)
Effect of foreign currency translation and other of VOBA	(82)	(202)	(191)
Reclassified to assets held-for-sale			0
Deferred policy acquisition costs and value of business acquired	11,983	11,560
Latin America
Deferred Policy Acquisition Costs and Present Value of Future Insurance Profits, Net [Abstract]
Balance at December 31, 2020	1,542	1,361	1,344
Capitalization of DAC	651	494	406
Amortization	418	361	311
Effect of foreign currency translation and other of DAC	175	48	(128)
Reclassified to assets held-for-sale (1)			0
Balance at January 1, 2021	1,950	1,542	1,361
Balance at December 31, 2020	545	591	748
Total amortization of VOBA	(50)	(49)	(61)
Effect of foreign currency translation and other of VOBA	2	3	(104)
Reclassified to assets held-for-sale			0
Balance at January 1, 2021	497	545	591
Deferred Policy Acquisition Costs and Present Value of Future Insurance Profits, Net, Ending Balance	2,447	2,087
Deferred Policy Acquisition Cost and Present Value of Future Profit [Line Items]
Deferred Policy Acquisition Cost	1,950	1,542	1,361	1,394
Capitalization of DAC	651	494	406
Deferred Policy Acquisition Costs, Amortization Expense	(418)	(361)	(311)
Effect of foreign currency translation and other of DAC	175	48	(128)
Reclassified to assets held-for-sale (1)			0
Present Value of Future Insurance Profits, Net	497	545	591	756
Total amortization of VOBA	(50)	(49)	(61)
Effect of foreign currency translation and other of VOBA	2	3	(104)
Reclassified to assets held-for-sale			0
Deferred policy acquisition costs and value of business acquired	2,447	2,087
EMEA
Deferred Policy Acquisition Costs and Present Value of Future Insurance Profits, Net [Abstract]
Balance at December 31, 2020	1,480	1,472	1,551
Capitalization of DAC	457	422	499
Amortization	332	311	360
Effect of foreign currency translation and other of DAC	13	(103)	(129)
Reclassified to assets held-for-sale (1)			(103)
Balance at January 1, 2021	1,618	1,480	1,472
Balance at December 31, 2020	127	154	236
Total amortization of VOBA	(16)	(20)	(29)
Effect of foreign currency translation and other of VOBA	2	(7)	(15)
Reclassified to assets held-for-sale			(34)
Balance at January 1, 2021	113	127	154
Deferred Policy Acquisition Costs and Present Value of Future Insurance Profits, Net, Ending Balance	1,731	1,607
Deferred Policy Acquisition Cost and Present Value of Future Profit [Line Items]
Deferred Policy Acquisition Cost	1,618	1,480	1,472	1,565
Capitalization of DAC	457	422	499
Deferred Policy Acquisition Costs, Amortization Expense	(332)	(311)	(360)
Effect of foreign currency translation and other of DAC	13	(103)	(129)
Reclassified to assets held-for-sale (1)			103
Present Value of Future Insurance Profits, Net	113	127	154	232
Total amortization of VOBA	(16)	(20)	(29)
Effect of foreign currency translation and other of VOBA	2	(7)	(15)
Reclassified to assets held-for-sale			(34)
Deferred policy acquisition costs and value of business acquired	1,731	1,607
MetLife Holdings
Deferred Policy Acquisition Costs and Present Value of Future Insurance Profits, Net [Abstract]
Balance at December 31, 2020	3,791	4,029	2,679
Capitalization of DAC	22	29	31
Amortization	255	267	313
Effect of foreign currency translation and other of DAC	(287)	0	0
Reclassified to assets held-for-sale (1)			0
Balance at January 1, 2021	3,271	3,791	4,029
Balance at December 31, 2020	28	31	33
Total amortization of VOBA	(3)	(3)	(7)
Effect of foreign currency translation and other of VOBA	(7)	0	0
Reclassified to assets held-for-sale			0
Balance at January 1, 2021	18	28	31
Deferred Policy Acquisition Costs and Present Value of Future Insurance Profits, Net, Ending Balance	3,289	3,819
Deferred Policy Acquisition Cost and Present Value of Future Profit [Line Items]
Deferred Policy Acquisition Cost	3,271	3,791	4,029	4,311
Capitalization of DAC	22	29	31
Deferred Policy Acquisition Costs, Amortization Expense	(255)	(267)	(313)
Effect of foreign currency translation and other of DAC	(287)	0	0
Reclassified to assets held-for-sale (1)			0
Present Value of Future Insurance Profits, Net	18	28	31	38
Total amortization of VOBA	(3)	(3)	(7)
Effect of foreign currency translation and other of VOBA	(7)	0	0
Reclassified to assets held-for-sale			0
Deferred policy acquisition costs and value of business acquired	3,289	3,819
Corporate and Other [Member]
Deferred Policy Acquisition Costs and Present Value of Future Insurance Profits, Net [Abstract]
Balance at December 31, 2020	30	32	31
Capitalization of DAC	8	8	100
Amortization	9	9	107
Effect of foreign currency translation and other of DAC	1	(1)	8
Reclassified to assets held-for-sale (1)			0
Balance at January 1, 2021	30	30	32
Balance at December 31, 2020	0	0	0
Total amortization of VOBA	0	0	0
Effect of foreign currency translation and other of VOBA	0	0	0
Reclassified to assets held-for-sale			0
Balance at January 1, 2021	0	0	0
Deferred Policy Acquisition Costs and Present Value of Future Insurance Profits, Net, Ending Balance	30	30
Deferred Policy Acquisition Cost and Present Value of Future Profit [Line Items]
Deferred Policy Acquisition Cost	30	30	32	31
Capitalization of DAC	8	8	100
Deferred Policy Acquisition Costs, Amortization Expense	(9)	(9)	(107)
Effect of foreign currency translation and other of DAC	1	(1)	8
Reclassified to assets held-for-sale (1)			0
Present Value of Future Insurance Profits, Net	0	0	0	$ 0
Total amortization of VOBA	0	0	0
Effect of foreign currency translation and other of VOBA	0	0	0
Reclassified to assets held-for-sale			$ 0
Deferred policy acquisition costs and value of business acquired	$ 30	$ 30