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Investments - Municipal bonds and other (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Municipal Bonds
Fair value	$ 21,725	$ 21,400
Threshold percentage of municipal to total carrying value	5.00%
Securities loaned
Fixed income and equity securities loaned	$ 506	502
Interest income on collateral, net of fees	1	1	$ 1
Short-term investments	1,191	810
Other	1,427	1,300
Other investment information
Below investment grade assets	2,830	$ 2,570
Fixed income securities and short-term investments deposited with regulatory authorities	21
Non-income producing fixed income securities and other investments	$ 15
Texas
Municipal Bonds
Percentage of municipal bonds carrying value	17.80%	17.60%
California
Municipal Bonds
Percentage of municipal bonds carrying value	15.00%	15.00%
Oregon
Municipal Bonds
Percentage of municipal bonds carrying value	12.60%	9.80%
New York
Municipal Bonds
Percentage of municipal bonds carrying value	7.00%	5.70%
New Jersey
Municipal Bonds
Percentage of municipal bonds carrying value	6.70%	5.00%
Illinois
Municipal Bonds
Percentage of municipal bonds carrying value	6.30%	4.60%
Policy loans
Securities loaned
Other	$ 557	$ 561
Agent loans
Securities loaned
Other	666	620
Bank loans
Securities loaned
Other	344	422
Real estate
Securities loaned
Other	292	228
Derivatives and other
Securities loaned
Other	125	30
Municipal
Municipal Bonds
Fair value	$ 1,755	$ 2,195