Insurance and Contractholder Liabilities - Other Segments - Discounted Liabilities (Details) - USD ($) $ in Billions	Dec. 31, 2018	Dec. 31, 2017
Short-duration Insurance Contracts Discounted Liabilities [Line Items]
Discounted liabilities	$ 4.2	$ 4.0
Aggregate amount of discount	$ 1.1	$ 1.0
Minimum [Member]
Short-duration Insurance Contracts Discounted Liabilities [Line Items]
Range of discount rates	4.20%	4.50%
Maximum [Member]
Short-duration Insurance Contracts Discounted Liabilities [Line Items]
Range of discount rates	5.20%	5.20%

The carrying amount as of the balance sheet date of loss reserves carried at present value.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 20
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 5.N.Q1)
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-Section 50
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- Definition

The discount rate used to reduce the estimated amount of loss reserves on short-duration contracts to present value.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 20
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 5.N.Q1)
-URI http://asc.fasb.org/extlink&oid=27015749&loc=d3e569934-122904

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-Section 50
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-URI http://asc.fasb.org/extlink&oid=99384497&loc=d3e14881-158438

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- Definition

Amount of cumulative discount related to the time value of money deducted from short-duration insurance contract liabilities that are reported at present value.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 40
-Section 50
-Paragraph 5
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=99384497&loc=d3e14881-158438

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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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