Investments (Fixed Maturity and Equity Securities Available-For-Sale - Narrative) (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Federal Home Loan Bank Stock		$ 791
Gross Unrealized OTTI Loss	$ (36)	(41)
Debt Securities, Available-for-sale	304,840	308,931
CMBS
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized OTTI Loss	0	0
Debt Securities, Available-for-sale	8,708	8,227
Non-income producing fixed maturity securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale	24	6
Gross Unrealized Gain	$ (1)	$ (4)

Other-than-temporary impairments on fixed maturity securities transferred to other comprehensive income loss.

No definition available.

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- Definition

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

+ References

No definition available.

+ Details

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- Definition

Amount of 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://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109979856&loc=d3e26610-111562

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

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- Definition

Federal Home Loan Bank (FHLB) stock represents an equity interest in a FHLB. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 325
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=75031641&loc=d3e63345-112809

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- Definition

Line items represent financial 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

No definition available.

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