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Investments - Municipal bonds and other (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Municipal Bonds
Fair value	$ 21,400	$ 23,261
Threshold percentage of municipal to total carrying value	5.00%
Securities loaned
Fixed income and equity securities loaned	$ 502	524
Interest income on collateral, net of fees	1	1	$ 2
Short-term investments	810	725
Other	1,300	1,254
Other investment information
Below investment grade assets	2,570	$ 2,910
Fixed income securities and short-term investments deposited with regulatory authorities	21
Non-income producing fixed income securities and other investments	$ 63
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	17.60%	16.90%
California
Municipal Bonds
Percentage of municipal bonds carrying value	15.00%	15.10%
Oregon
Municipal Bonds
Percentage of municipal bonds carrying value	9.80%	9.40%
New York
Municipal Bonds
Percentage of municipal bonds carrying value	5.70%	5.20%
Policy loans
Securities loaned
Other	$ 561	$ 561
Agent loans
Securities loaned
Other	620	538
Bank loans
Securities loaned
Other	422	437
Real estate
Securities loaned
Other	228	157
Derivatives and other
Securities loaned
Other	30	122
Municipal
Municipal Bonds
Fair value	$ 2,195	$ 2,273