Income Taxes - Differences Between Statutory Income Tax Rate and Effective Income Tax Rate (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Increase (decrease) resulting from:
Tax at statutory rate	$ 140	$ (220)	$ 196	$ (294)
Tax-exempt income from municipal bonds	(5)	(5)	(10)	(10)
Dividend received exclusion	(6)	(5)	(11)	(10)
Other	3	(5)	0	(6)
Total provision (benefit) for income taxes	$ 132	$ (235)	$ 175	$ (320)
Increase (decrease) resulting from:
Tax at statutory rate	21.00%	21.00%	21.00%	21.00%
Tax-exempt income from municipal bonds, Percent	(0.80%)	0.50%	(1.10%)	0.70%
Dividend received exclusion, Percent	(0.90%)	0.50%	(1.20%)	0.70%
Other	0.50%	0.30%	0.00%	0.40%
Provision for income taxes	19.80%	22.30%	18.70%	22.80%