Below investment grade assets included in fixed income securities.

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This element represents the fixed income securities that do not produce any income.

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This element represents the amount of municipal bonds as a percentage of total carrying value.

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The minimum percentage of municipal bonds to total carrying value that is used as a threshold for disclosure.

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Interest earned on collateral received for loaned securities and invested in short-term investments and fixed income securities, net of fees.

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Threshold percentage which the entity uses for disclosure.

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Carrying amount of cash and investment securities on deposit with state regulatory authorities in connection with capital requirements.

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Amount of securities loaned to entities in exchange for collateral, not subject to a master netting arrangement.

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Investments - Municipal bonds and other (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Municipal Bonds
Threshold percentage of municipal to total carrying value	5.00%	5.00%
Securities loaned
Fixed income and equity securities loaned	$ 524	$ 520
Interest income on collateral, net of fees	1	2	$ 1
Other investment information
Below investment grade assets	2,910	$ 3,170
Fixed income securities and short-term investments deposited with regulatory authorities	21
Non-income producing fixed income securities and other investments	$ 32
Shareholders' equity \| Concentration of credit risk \| Minimum
Municipal Bonds
Percentage of credit concentration risk of single issuer and affiliates of shareholder's equity	10.00%
Texas
Municipal Bonds
Percentage of municipal bonds carrying value	16.90%	16.90%
California
Municipal Bonds
Percentage of municipal bonds carrying value	15.10%	14.90%
Oregon
Municipal Bonds
Percentage of municipal bonds carrying value	9.40%	9.00%
New York
Municipal Bonds
Percentage of municipal bonds carrying value	5.20%	5.10%
Michigan
Municipal Bonds
Percentage of municipal bonds carrying value	5.00%	5.20%
New Jersey
Municipal Bonds
Percentage of municipal bonds carrying value	4.80%	5.40%