Income Taxes - Reconciliation of Expected Income Tax Expense at Federal Statutory Rate to the Applicable Income Tax Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Income Tax Disclosure [Abstract]
Tax at statutory rate	$ 435	$ 411	$ 1,218	$ 1,232
State income tax, at statutory rates, net of federal tax benefit	106	85	289	270
Tax credits and benefits, net of related expenses	(140)	(96)	(284)	(236)
Exam resolutions	(1)	0	(98)	0
Tax-exempt income	(38)	(40)	(105)	(115)
Other items	(12)	71	122	117
Total income tax provision	$ 350	$ 431	$ 1,142	$ 1,268