Equity (Components of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance beginning of period	$ 7,427	$ 5,366	$ 4,767
OCI before reclassifications	(9,114)	5,994	606
Deferred income tax benefit (expense)	1,921	(1,552)	(300)
AOCI before reclassifications, net of income tax	234	9,808	5,073
Amounts reclassified from AOCI	651	(1,147)	443
Deferred income tax benefit (expense)	(167)	400	(150)
Amounts reclassified from AOCI, net of income tax	484	(747)	293
Balance end of period	1,722	7,427	5,366
Unrealized Investment Gains (Losses), Net of Related Offsets
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance beginning of period	12,757	10,785	10,311
OCI before reclassifications	(8,735)	5,392	800
Deferred income tax benefit (expense)	1,961	(1,732)	(338)
AOCI before reclassifications, net of income tax	5,983	14,445	10,773
Amounts reclassified from AOCI	14	(289)	21
Deferred income tax benefit (expense)	(3)	87	(9)
Amounts reclassified from AOCI, net of income tax	11	(202)	12
Balance end of period	7,042	12,757	10,785
Unrealized Gains (Losses) on Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance beginning of period	905	1,865	1,458
OCI before reclassifications	157	(140)	344
Deferred income tax benefit (expense)	(41)	47	(100)
AOCI before reclassifications, net of income tax	1,021	1,772	1,702
Amounts reclassified from AOCI	517	(1,025)	229
Deferred income tax benefit (expense)	(135)	356	(66)
Amounts reclassified from AOCI, net of income tax	382	(669)	163
Balance end of period	1,613	905	1,865
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance beginning of period	(4,390)	(5,312)	(4,950)
OCI before reclassifications	(679)	765	(476)
Deferred income tax benefit (expense)	36	125	114
AOCI before reclassifications, net of income tax	(5,033)	(4,422)	(5,312)
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	(4,905)	(4,390)	(5,312)
Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance beginning of period	(1,845)	(1,972)	(2,052)
OCI before reclassifications	143	(23)	(62)
Deferred income tax benefit (expense)	(35)	8	24
AOCI before reclassifications, net of income tax	(1,737)	(1,987)	(2,090)
Amounts reclassified from AOCI	120	167	193
Deferred income tax benefit (expense)	(29)	(43)	(75)
Amounts reclassified from AOCI, net of income tax	91	124	118
Balance end of period	(2,028)	(1,845)	$ (1,972)
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)