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, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Increase (decrease) resulting from:
Tax at statutory rate	$ 81	$ 140	$ 281	$ 196
Tax-exempt income from municipal bonds	(6)	(5)	(11)	(10)
Dividend received exclusion	(5)	(6)	(10)	(11)
Other	4	3	12	0
Total provision for income taxes	$ 74	$ 132	$ 272	$ 175
Increase (decrease) resulting from:
Tax at statutory rate	21.00%	21.00%	21.00%	21.00%
Tax-exempt income from municipal bonds, Percent	(1.60%)	(0.80%)	(0.80%)	(1.10%)
Dividend received exclusion, Percent	(1.30%)	(0.90%)	(0.70%)	(1.20%)
Other	1.10%	0.50%	0.80%	0.00%
Provision for income taxes	19.20%	19.80%	20.30%	18.70%