Income Tax (Reconciliation of Income Tax Provision between US Statutory Rate and As Reported for Continuing Operations) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income tax expense benefit continuing operations income tax reconciliation
Tax provision at U.S. statutory rate			$ 1,455	$ 1,427	$ 1,325
Dividend received deduction			(34)	(37)	(35)
Tax-exempt income			(45)	(64)	(29)
Prior year tax (1), (2)			(27)	(179)	(197)
Low income housing tax credits			(202)	(254)	(284)
Other tax credits			(45)	(52)	(79)
Foreign tax rate differential expense (benefit)			414	395	335
Change in valuation allowance			(5)	(22)	(2)
Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount			(2)	(2)	67
Deferred Federal Income Tax Expense (Benefit)			(115)	(235)	342
Provision for income tax expense (benefit)			1,509	886	1,179
MetLife Hong Kong
Income tax expense benefit continuing operations income tax reconciliation
Foreign tax rate differential expense (benefit)				61
Provision for income tax expense (benefit)				40
Brighthouse Financial, Inc
Income tax expense benefit continuing operations income tax reconciliation
Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount					69
MetLife Seguros de Retiro [Member]
Income tax expense benefit continuing operations income tax reconciliation
Foreign tax rate differential expense (benefit)			60
MetLife Russia [Member]
Income tax expense benefit continuing operations income tax reconciliation
Foreign tax rate differential expense (benefit)			24
Impact of U.S. Tax Reform
Income tax expense benefit continuing operations income tax reconciliation
Tax provision at U.S. statutory rate					12
Other Adjustments, Amount			0	(326)	78
Deferred Federal Income Tax Expense (Benefit)				(9)	(402)
Provision for income tax expense (benefit)				(326)	66
Alternative Minimum Tax Credits
Income tax expense benefit continuing operations income tax reconciliation
Deferred Federal Income Tax Expense (Benefit)				(9)	0
Tax Rate Change [Member]
Income tax expense benefit continuing operations income tax reconciliation
Other Adjustments, Amount					(390)
Patient Protection and Affordable Care Act excise tax [Member]
Income tax expense benefit continuing operations income tax reconciliation
Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount					18
Settlement with Taxing Authority
Income tax expense benefit continuing operations income tax reconciliation
Prior year tax (1), (2)			(40)	(158)	(168)
Provision for income tax expense (benefit)	$ (158)	$ (168)
GILTI [Member] | Impact of U.S. Tax Reform
Income tax expense benefit continuing operations income tax reconciliation
Effective Income Tax Rate Reconciliation, Tax Contingency, Foreign, Amount			$ 43	12
Provision for income tax expense (benefit)				35	45
Foreign Tax Authority | Impact of U.S. Tax Reform
Income tax expense benefit continuing operations income tax reconciliation
Repatriation of Foreign Earnings				317	468
CHILE
Income tax expense benefit continuing operations income tax reconciliation
Foreign tax rate differential expense (benefit)					17
UNITED KINGDOM
Income tax expense benefit continuing operations income tax reconciliation
Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount					(36)
ARGENTINA
Income tax expense benefit continuing operations income tax reconciliation
Foreign tax rate differential expense (benefit)					$ 13
Change in Accounting Method Accounted for as Change in Estimate [Member] | GILTI [Member] | Impact of U.S. Tax Reform
Income tax expense benefit continuing operations income tax reconciliation
Provision for income tax expense (benefit)				$ (23)