Represents the number of securities which had unrealized losses greater than 10% of book value for 12 months or more.

No definition available.

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- Definition

This item represents the excess of amortized cost basis over fair value of securities that have been in a loss position for twelve months or longer for those securities which are categorized neither as held-to-maturity nor trading securities and which have unrealized losses greater than 10% of book value.

+ References

No definition available.

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- Definition

Managers Managing Investment Portfolio, Investment Guidelines, Percent of Externally Managed Portfolio

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Number of Outside Managers Managing Investment Portfolio

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- Definition

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
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- Definition

Interest, dividends, rents, ancillary and other revenues earned but not yet received by the entity on its investments.

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- Definition

The total amount of cash and securities held by third party trustees pursuant to terms of debt instruments or other agreements as of the date of each statement of financial position presented, which can be used by the trustee only to pay the noncurrent portion of specified obligations.

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- Definition

The minimum amount the entity agreed to spend under the long-term purchase commitment.

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No definition available.

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- Definition

Amount of cash inflow from sale of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Minimum amount to be expended to satisfy the terms of arrangements in which the entity has agreed to expend funds to procure goods or services, excluding long-term purchase commitments or unconditional purchase obligations.

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Investments and Cash - Narrative (Details) $ in Millions	1 Months Ended	3 Months Ended
Investments and Cash - Narrative (Details) $ in Millions	Feb. 28, 2017 USD ($)	Mar. 31, 2019 USD ($) Security manager	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($) Security
Investment [Line Items]
Proceeds from sale of fixed-maturity securities available-for-sale		$ 471	$ 409
Accrued investment income		$ 92		$ 91
Number of securities with unrealized losses greater than 10% of book value for 12 months or more \| Security		37		38
Total unrealized losses for securities having losses greater than 10% of book value for 12 months or more		$ 33		$ 43
Assets held-in-trust		$ 269		266
Number of outside managers managing investment portfolio \| manager		7
Future Equity Investments [Member]
Investment [Line Items]
Long-term purchase commitment, amount	$ 100
Purchase Commitment, Remaining Minimum Amount Committed		$ 83
AGL Subsidiaries [Member]
Investment [Line Items]
Assets held-in-trust		$ 1,873		$ 1,855
Maximum [Member] \| Standard & Poor's, A- Rating [Member] \| Moody's, A3 Rating [Member]
Investment [Line Items]
Managers Managing Investment Portfolio, Investment Guidelines, Percent of Externally Managed Portfolio		15.00%