Investments (Net Investment Gains Losses - Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Gains (losses) from foreign currency transactions	$ 65	$ 80
Gain (Loss) on Sales of Loans, Net	(21)	(12)
Non-investment portfolio gains (losses) (2)	(76)	103
Gain (Loss) on Sale of Debt Investments	(95)	$ (2)
FVO Common Stock [Member] \| Brighthouse Financial, Inc
Schedule of Available-for-sale Securities [Line Items]
Non-investment portfolio gains (losses) (2)	$ 168

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 830
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6450222&loc=d3e30840-110895

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 45
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-URI http://asc.fasb.org/extlink&oid=64836518&loc=d3e30690-110894

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-Publisher FASB
-Name Accounting Standards Codification
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The difference between the carrying value and the sale price of debt securities, not separately or otherwise categorized as trading, available-for-sale, or held-to-maturity. This element refers to the gain (loss) included in earnings and not to the cash proceeds of the sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 225
-Section S99
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-Subparagraph (SX 210.7-04.3(a))
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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Amount of gain (loss) on sale or disposal of other assets.

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The net gain (loss) resulting from a sale of loans, including adjustments to record loans classified as held-for-sale at the lower-of-cost-or-market and fair value adjustments to loan held for investment purposes.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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