Insurance (Obligations Under Funding Agreements - Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Insurance [Abstract]
Funding agreements issued to certain SPEs	$ 0	$ 0	$ 1,400
Funding Agreements Repaid To Certain Special Purpose Entities	6	6	$ 3,400
Outstanding Funding Agreements To Certain Special Purpose Entities	$ 136	$ 141

Amount of funding agreements issued during current year to certain special purpose entities that have issued debt securities for which payment of interest and principal is secured by such funding agreements.

No definition available.

Name:	bhf_FundingAgreementsIssuedToCertainSpecialPurposeEntities
Namespace Prefix:	bhf_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration