Separation of Brighthouse (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
	Aug. 04, 2017	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Reduction of long-term debt				$ 944	$ 0
Non-investment portfolio gains (losses) (2)		$ (238)	$ (113)	(314)	(10)
Brighthouse Financial, Inc
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Common Stock, Shares, Owned by MetLife, INC.	22,996,436
Discontinued Operation, Equity Method Investment Retained after Disposal, Ownership Interest after Disposal	19.20%
Equity Method Investment, Quoted Market Value						$ 1,300
Discontinued Operation, Separation Costs			330		407
Discontinued Operation, Other fees and cost required			$ 294		$ 294
Reduction of long-term debt				944
FVO Common Stock | Brighthouse Financial, Inc
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Non-investment portfolio gains (losses) (2)		$ (159)		$ (327)