Equity (Components of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance beginning of period	$ 1,722	$ 7,427	$ 5,366
OCI before reclassifications	15,047	(9,114)	5,994
Deferred income tax benefit (expense)	(3,339)	1,921	(1,552)
AOCI before reclassifications, net of income tax	13,430	234	9,808
Amounts reclassified from AOCI	(415)	651	(1,147)
Deferred income tax benefit (expense)	16	(167)	400
Amounts reclassified from AOCI, net of income tax	(399)	484	(747)
Balance end of period	13,052	1,722	7,427
Unrealized Investment Gains (Losses), Net of Related Offsets
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance beginning of period	7,042	12,757	10,785
OCI before reclassifications	14,850	(8,735)	5,392
Deferred income tax benefit (expense)	(3,408)	1,961	(1,732)
AOCI before reclassifications, net of income tax	18,484	5,983	14,445
Amounts reclassified from AOCI	(265)	14	(289)
Deferred income tax benefit (expense)	61	(3)	87
Amounts reclassified from AOCI, net of income tax	(204)	11	(202)
Balance end of period	18,283	7,042	12,757
Unrealized Gains (Losses) on Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance beginning of period	1,613	905	1,865
OCI before reclassifications	328	157	(140)
Deferred income tax benefit (expense)	34	(41)	47
AOCI before reclassifications, net of income tax	1,975	1,021	1,772
Amounts reclassified from AOCI	(268)	517	(1,025)
Deferred income tax benefit (expense)	(27)	(135)	356
Amounts reclassified from AOCI, net of income tax	(295)	382	(669)
Balance end of period	1,698	1,613	905
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance beginning of period	(4,905)	(4,390)	(5,312)
OCI before reclassifications	(43)	(679)	765
Deferred income tax benefit (expense)	21	36	125
AOCI before reclassifications, net of income tax	(4,927)	(5,033)	(4,422)
Amounts reclassified from AOCI	0	0	0
Deferred income tax benefit (expense)	0	0	0
Amounts reclassified from AOCI, net of income tax	0	0	0
Balance end of period	(4,927)	(4,905)	(4,390)
Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance beginning of period	(2,028)	(1,845)	(1,972)
OCI before reclassifications	(88)	143	(23)
Deferred income tax benefit (expense)	14	(35)	8
AOCI before reclassifications, net of income tax	(2,102)	(1,737)	(1,987)
Amounts reclassified from AOCI	118	120	167
Deferred income tax benefit (expense)	(18)	(29)	(43)
Amounts reclassified from AOCI, net of income tax	100	91	124
Balance end of period	(2,002)	(2,028)	(1,845)
Brighthouse Financial, Inc
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI			(2,512)
Deferred income tax benefit (expense)			878
Amounts reclassified from AOCI, net of income tax			(1,634)
Brighthouse Financial, Inc | Unrealized Investment Gains (Losses), Net of Related Offsets
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI			(2,286)
Deferred income tax benefit (expense)			800
Amounts reclassified from AOCI, net of income tax			(1,486)
Brighthouse Financial, Inc | Unrealized Gains (Losses) on Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI			(305)
Deferred income tax benefit (expense)			107
Amounts reclassified from AOCI, net of income tax			(198)
Brighthouse Financial, Inc | Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI			51
Deferred income tax benefit (expense)			(19)
Amounts reclassified from AOCI, net of income tax			32
Brighthouse Financial, Inc | Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI			28
Deferred income tax benefit (expense)			(10)
Amounts reclassified from AOCI, net of income tax			$ 18
MetLife Afore
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI		92
MetLife Afore | Unrealized Investment Gains (Losses), Net of Related Offsets
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI		0
MetLife Afore | Unrealized Gains (Losses) on Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI		0
MetLife Afore | Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI		92
MetLife Afore | Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI		0
Accounting Standards Update 2016-01
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI		(425)
Deferred income tax benefit (expense)		1,337
Amounts reclassified from AOCI, net of income tax		912
Accounting Standards Update 2016-01 | Unrealized Investment Gains (Losses), Net of Related Offsets
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI		(425)
Deferred income tax benefit (expense)		1,473
Amounts reclassified from AOCI, net of income tax		1,048
Accounting Standards Update 2016-01 | Unrealized Gains (Losses) on Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI		0
Deferred income tax benefit (expense)		210
Amounts reclassified from AOCI, net of income tax		210
Accounting Standards Update 2016-01 | Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI		0
Deferred income tax benefit (expense)		36
Amounts reclassified from AOCI, net of income tax		36
Accounting Standards Update 2016-01 | Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI		0
Deferred income tax benefit (expense)		(382)
Amounts reclassified from AOCI, net of income tax		$ (382)
Accounting Standards Update 2017-12
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI	26
Deferred income tax benefit (expense)	(5)
Amounts reclassified from AOCI, net of income tax	21
Accounting Standards Update 2017-12 | Unrealized Investment Gains (Losses), Net of Related Offsets
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI	4
Deferred income tax benefit (expense)	(1)
Amounts reclassified from AOCI, net of income tax	3
Accounting Standards Update 2017-12 | Unrealized Gains (Losses) on Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI	22
Deferred income tax benefit (expense)	(4)
Amounts reclassified from AOCI, net of income tax	18
Accounting Standards Update 2017-12 | Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI	0
Deferred income tax benefit (expense)	0
Amounts reclassified from AOCI, net of income tax	0
Accounting Standards Update 2017-12 | Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI	0
Deferred income tax benefit (expense)	0
Amounts reclassified from AOCI, net of income tax	$ 0