Separation (New Financing Arrangements - Narrative) (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Aug. 02, 2017	Jul. 21, 2017	Apr. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Secured Debt		$ 1,220		$ 1,220					$ 1,274
Preferred Stock, Shares Issued		25,500,000		25,500,000					25,500,000
Other General and Administrative Expense		$ 352	$ 336	$ 1,215	$ 1,090
Brighthouse Financial, Inc
Debt Instrument [Line Items]
Preferred Stock, Shares Issued	50,000
Preferred Stock, Dividend Payment Rate, Variable	0.065
Proceeds from Issuance of Preferred Stock and Preference Stock	$ 49
Debt Instrument, Face Amount						$ 500
Line of Credit Facility, Maximum Borrowing Capacity	536						$ 600	$ 3,000
Line of Credit Facility, Current Borrowing Capacity							$ 500
Brighthouse Financial, Inc | 2027 Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 1,500
Debt Instrument, Maturity Date	Jun. 30, 2027
Debt Instrument, Interest Rate, Stated Percentage	3.70%
Brighthouse Financial, Inc | 2047 Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 1,500
Debt Instrument, Maturity Date	Jun. 30, 2047
Debt Instrument, Interest Rate, Stated Percentage		4.70%		4.70%
Brighthouse Financial, Inc | Brighthouse Reinsurance Company of Delaware [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity								$ 10,000