Income Taxes - Differences Between Statutory Income Tax Rate and Effective Income Tax Rate (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Increase (decrease) resulting from:
Tax at statutory rate	$ 56	$ (74)
Tax-exempt income from municipal bonds	(5)	(5)
Dividend received exclusion	(5)	(5)
Other	(3)	(1)
Total provision (benefit) for income taxes	$ 43	$ (85)
Increase (decrease) resulting from:
Tax at statutory rate	21.00%	21.00%
Tax-exempt income from municipal bonds, Percent	(1.90%)	1.40%
Dividend received exclusion, Percent	(1.90%)	1.40%
Other	(1.20%)	0.40%
Provision for income taxes	16.00%	24.20%