Income Taxes - Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Tax provision at U.S. federal statutory rate	$ 91	$ 122	$ 321	$ 419
Tax-exempt interest	(9)	(10)	(26)	(31)
Other	(11)	2	(1)	25
Income tax expense	92	101	300	360
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount	6	(1)	14	6
Effective Income Tax Rate Reconciliation, Tax Credit, Amount	$ 7	$ 8	$ 10	$ 9