Investments (Net Investment Gains Losses - Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Debt Securities, Available-for-sale [Line Items]
Gains (losses) from foreign currency transactions	$ (100)	$ (14)	$ (82)	$ (52)
Gain (Loss) on Sales of Loans, Net	4	29	(32)	3
Non-investment portfolio gains (losses) (2)	76	1,081	390	1,091
Gain (Loss) on Sale of Debt Investments	$ 123	284	(18)	325
Brighthouse Financial, Inc
Debt Securities, Available-for-sale [Line Items]
Gain (Loss) on Sales of Loans, Net		47		47
Non-investment portfolio gains (losses) (2)		(1,016)		(1,016)
Gain (Loss) on Sale of Debt Investments		276		276
FVO Common Stock \| Brighthouse Financial, Inc
Debt Securities, Available-for-sale [Line Items]
Non-investment portfolio gains (losses) (2)		$ (45)	$ 327	$ (45)

Amount before tax of foreign currency transaction realized gain (loss) recognized in the income statement.

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