Separation (Contributions of Entities, Mergers and Dividends - Narrative) (Details) - USD ($) $ in Billions	Aug. 03, 2017	Jun. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Common Stock, Shares, Issued		1,166,331,934	1,164,029,985
Common Stock, Shares Authorized		3,000,000,000	3,000,000,000
Minimum | Spinoff [Member]
Debt Instrument [Line Items]
BHF Common Stock		80.10%
Subsequent Event [Member] | Spinoff [Member]
Debt Instrument [Line Items]
Common Stock, Shares, Issued	96,776,670
Common Stock, Shares Authorized	119,773,106
BHF Common Stock	80.80%
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries	$ 1.8