Month and year the the entity entered into the derivative contract, in YYYY-MM format.

No definition available.

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- Definition

The aggregate premiums received on derivative contracts at the contract inception dates.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Definition

Month and year the derivative contract matures, in YYYY-MM format.

+ References

No definition available.

+ Details

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- Definition

Represents the undiscounted liability assuming the contracts are settled on their future expiration dates based on the index values at the most recent balance sheet date.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Percentage of decline in equity index values.

+ References

No definition available.

+ Details

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- Definition

The aggregate fair value of assets that are already posted, at the end of the reporting period, as collateral for derivative instruments with credit-risk-related contingent features.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4H
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624258-113959

+ Details

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Balance Type:	debit
Period Type:	instant

- Definition

Average remaining period until maturity of the derivative contract, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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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.

+ Details

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Data Type:	xbrli:stringItemType
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Period Type:	duration

- Definition

Aggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5618551-113959

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

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- Details

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Derivative contracts - Narrative (Detail) - Not Designated as Hedging Instrument [Member] - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Derivative [Line Items]
Collateral posting requirements under contracts with collateral provisions	$ 0
Equity Index Put Options [Member]
Derivative [Line Items]
Derivative contract pre-tax gains (losses)	$ (1,393,000,000)	$ 770,000,000
Derivative maturity month and year	2023-02
Weighted average life of unexpired derivative contracts	1 year 6 months
Premiums received at contract inception dates	$ 2,500,000,000
Aggregate intrinsic value of equity index put option contracts	$ 2,000,000,000.0		$ 397,000,000
Equity Index Put Options [Member] \| Minimum [Member]
Derivative [Line Items]
Percentage of decline in index values	20.00%
Equity Index Put Options [Member] \| Maximum [Member]
Derivative [Line Items]
Percentage of decline in index values	25.00%
Derivative inception month and year	2008-03