Income Taxes - Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Income Tax Disclosure [Abstract]
Tax provision at U.S. federal statutory rate	$ 114	$ 63
Tax-exempt interest	(9)	(11)
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Other, Amount	7	5
Effective Income Tax Rate Reconciliation, Tax Expense (Benefit), Share-based Payment Arrangement, Amount	(10)	(1)
Other	4	2
Income tax expense	$ 98	$ 54