Segment Information (Earnings) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenues
Premiums	$ 9,405	$ 9,178
Universal life and investment-type product policy fees	1,365	1,392
Net investment income	4,908	3,745
Other revenues	494	474
Net investment gains (losses)	15	(333)
Net derivative gains (losses)	115	349
Total revenues	16,302	14,805
Expenses
Policyholder benefits and claims and policyholder dividends	9,372	9,015
Interest credited to policyholder account balances	1,961	769
Capitalization of DAC	(812)	(796)
Amortization of DAC and VOBA	624	693
Amortization of negative VOBA	(10)	(22)
Interest expense on debt	234	286
Other expenses	3,189	3,204
Total expenses	14,558	13,149
Provision for income tax expense (benefit)	359	399
Income (loss) from continuing operations, net of income tax	1,385	1,257
Operating Segments
Revenues
Premiums	9,405	9,178
Universal life and investment-type product policy fees	1,338	1,360
Net investment income	4,281	4,219
Other revenues	424	391
Net investment gains (losses)	0	0
Net derivative gains (losses)	0	0
Total revenues	15,448	15,148
Expenses
Policyholder benefits and claims and policyholder dividends	9,241	8,968
Interest credited to policyholder account balances	1,248	1,117
Capitalization of DAC	(812)	(795)
Amortization of DAC and VOBA	655	697
Amortization of negative VOBA	(10)	(21)
Interest expense on debt	234	286
Other expenses	3,101	3,110
Total expenses	13,657	13,362
Provision for income tax expense (benefit)	335	357
Adjusted earnings	1,456	1,429
Operating Segments | U.S.
Revenues
Premiums	5,567	5,217
Universal life and investment-type product policy fees	270	258
Net investment income	1,719	1,662
Other revenues	221	204
Net investment gains (losses)	0	0
Net derivative gains (losses)	0	0
Total revenues	7,777	7,341
Expenses
Policyholder benefits and claims and policyholder dividends	5,373	5,138
Interest credited to policyholder account balances	501	407
Capitalization of DAC	(114)	(106)
Amortization of DAC and VOBA	114	115
Amortization of negative VOBA	0	0
Interest expense on debt	2	2
Other expenses	993	961
Total expenses	6,869	6,517
Provision for income tax expense (benefit)	184	171
Adjusted earnings	724	653
Operating Segments | Asia
Revenues
Premiums	1,699	1,748
Universal life and investment-type product policy fees	406	394
Net investment income	880	795
Other revenues	16	15
Net investment gains (losses)	0	0
Net derivative gains (losses)	0	0
Total revenues	3,001	2,952
Expenses
Policyholder benefits and claims and policyholder dividends	1,319	1,343
Interest credited to policyholder account balances	403	351
Capitalization of DAC	(479)	(465)
Amortization of DAC and VOBA	307	314
Amortization of negative VOBA	(9)	(15)
Interest expense on debt	0	0
Other expenses	955	952
Total expenses	2,496	2,480
Provision for income tax expense (benefit)	149	145
Adjusted earnings	356	327
Operating Segments | Latin America
Revenues
Premiums	646	699
Universal life and investment-type product policy fees	284	282
Net investment income	296	276
Other revenues	12	8
Net investment gains (losses)	0	0
Net derivative gains (losses)	0	0
Total revenues	1,238	1,265
Expenses
Policyholder benefits and claims and policyholder dividends	597	646
Interest credited to policyholder account balances	94	98
Capitalization of DAC	(94)	(94)
Amortization of DAC and VOBA	78	60
Amortization of negative VOBA	0	0
Interest expense on debt	1	2
Other expenses	366	338
Total expenses	1,042	1,050
Provision for income tax expense (benefit)	62	75
Adjusted earnings	134	140
Operating Segments | EMEA
Revenues
Premiums	542	551
Universal life and investment-type product policy fees	103	112
Net investment income	74	75
Other revenues	14	16
Net investment gains (losses)	0	0
Net derivative gains (losses)	0	0
Total revenues	733	754
Expenses
Policyholder benefits and claims and policyholder dividends	284	294
Interest credited to policyholder account balances	24	25
Capitalization of DAC	(117)	(118)
Amortization of DAC and VOBA	92	106
Amortization of negative VOBA	(1)	(6)
Interest expense on debt	0	0
Other expenses	338	351
Total expenses	620	652
Provision for income tax expense (benefit)	27	21
Adjusted earnings	86	81
Operating Segments | MetLife Holdings
Revenues
Premiums	927	950
Universal life and investment-type product policy fees	274	314
Net investment income	1,287	1,352
Other revenues	67	67
Net investment gains (losses)	0	0
Net derivative gains (losses)	0	0
Total revenues	2,555	2,683
Expenses
Policyholder benefits and claims and policyholder dividends	1,648	1,550
Interest credited to policyholder account balances	226	236
Capitalization of DAC	(6)	(10)
Amortization of DAC and VOBA	63	100
Amortization of negative VOBA	0	0
Interest expense on debt	2	2
Other expenses	227	276
Total expenses	2,160	2,154
Provision for income tax expense (benefit)	78	104
Adjusted earnings	317	425
Operating Segments | Corporate & Other
Revenues
Premiums	24	13
Universal life and investment-type product policy fees	1	0
Net investment income	25	59
Other revenues	94	81
Net investment gains (losses)	0	0
Net derivative gains (losses)	0	0
Total revenues	144	153
Expenses
Policyholder benefits and claims and policyholder dividends	20	(3)
Interest credited to policyholder account balances	0	0
Capitalization of DAC	(2)	(2)
Amortization of DAC and VOBA	1	2
Amortization of negative VOBA	0	0
Interest expense on debt	229	280
Other expenses	222	232
Total expenses	470	509
Provision for income tax expense (benefit)	(165)	(159)
Adjusted earnings	(161)	(197)
Significant Reconciling Items
Revenues
Premiums	0	0
Universal life and investment-type product policy fees	27	32
Net investment income	627	(474)
Other revenues	70	83
Net investment gains (losses)	15	(333)
Net derivative gains (losses)	115	349
Total revenues	854	(343)
Expenses
Policyholder benefits and claims and policyholder dividends	131	47
Interest credited to policyholder account balances	713	(348)
Capitalization of DAC	0	(1)
Amortization of DAC and VOBA	(31)	(4)
Amortization of negative VOBA	0	(1)
Interest expense on debt	0	0
Other expenses	88	94
Total expenses	901	(213)
Provision for income tax expense (benefit)	$ 24	$ 42