Non-credit related portion of other-than-temporary impairment charges taken for securities still owned.

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Number of available-for-sale securities in an unrealized loss position.

+ References

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Percentage (based on fair value) of available for sale fixed maturities that are in an unrealized loss position and rated investment grade.

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Percentage based on unrealized loss of available for sale fixed maturities that are in an unrealized loss position and rated investment grade.

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Line items represent reporting concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 12
-Sentence Column A

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

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The amount of other than temporary impairment losses on investments in debt and equity securities categorized as Available-for-sale which have been recognized in earnings during the period. Such impairment losses consist of other than temporary impairments (OTTI) on equity securities, credit losses on investments in debt securities, and when the entity intends to sell an impaired debt security or it is more likely than not that the entity will be required to sell the impaired debt security before recovery of its amortized cost basis.

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Investments - Narrative (Details) $ in Millions	3 Months Ended		9 Months Ended
Investments - Narrative (Details) $ in Millions	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) security	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)
Investment [Line Items]
Percentage (based on amount of unrealized loss) of available for sale fixed maturities that are in an unrealized loss position and rated investment grade			95.00%
Percentage (based on fair value) of available for sale fixed maturities that are in an unrealized loss position and rated investment grade			96.00%
Other than temporary impairment charges	$ 2	$ 38	$ 3	$ 53
Residential MBS
Investment [Line Items]
Non-credit related portion of other-than-temporary impairment charges taken for securities still owned	144		144		$ 158
Gross unrealized losses on fixed maturities	(9)		(9)		(6)
Other than temporary impairment charges			1
Securities with non-credit other-than-temporary impairment charges
Investment [Line Items]
Gross unrealized gains	130		130		137
Gross unrealized losses	(4)		(4)		(4)
Fixed maturities
Investment [Line Items]
Gross unrealized losses on fixed maturities	(543)		$ (543)		$ (82)
Number of available for sale securities in an unrealized loss position \| security			2,392
Other than temporary impairment charges	2	15	$ 3	16
Gross gains			19	32
Gross losses			(8)	(4)
Corporate bonds
Investment [Line Items]
Other than temporary impairment charges			2
Equity securities
Investment [Line Items]
Other than temporary impairment charges	$ 0	$ 29	$ 0	49
Gross gains				36
Gross losses				$ (6)