Investments and Cash - Net Investment Income (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Net Investment Income
Gross investment income	$ 100	$ 102	$ 305	$ 329
Investment expenses	(2)	(3)	(7)	(7)
Net investment income	98	99	298	322
Fixed Maturities, Managed Externally [Member]
Net Investment Income
Gross investment income	75	74	224	224
Fixed Maturities, Managed Internally [Member]
Net Investment Income
Gross investment income	$ 25	$ 28	$ 81	$ 105

Represents the total of interest and dividend income, including any amortization and accretion (as applicable) of discounts and premiums, earned from (1) loans and leases whether held-for-sale or held-in-portfolio; (2) investment securities; (3) federal funds sold; (4) securities purchased under agreements to resell; (5) investments in banker's acceptances, commercial paper, or certificates of deposit; (6) dividend income; or (7) other investments not otherwise specified herein.

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Amount of expenses related to the generation of investment income.

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Amount, after investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments.

+ References

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