Accumulated Other Comprehensive Income - Summary of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023		Dec. 31, 2022		Dec. 31, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	$ 36,608	[1]	$ 56,261		$ 56,060
Other net changes	4,490		(21,512)		(6,503)
Balance at end of period	40,958	[1]	36,608	[1]	56,261
Accumulated other comprehensive income, tax expense (benefit)	1,549		(6,812)		(2,033)
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(22,621)		(1,109)		5,394
Other net changes	4,490		(21,512)		(6,503)
Balance at end of period	(18,131)		(22,621)		(1,109)
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-Sale, Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other net changes	2,653		(22,106)		(6,492)
Accumulated other comprehensive income, tax expense (benefit)	886		(6,994)		(2,029)
Net Unrealized Gain (Loss) On Securities Transferred To Held-To-Maturity
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other net changes			13,851
Accumulated other comprehensive income, tax expense (benefit)			(4,377)
Other Reclassifications Included in Other Revenue from Sale of Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other net changes	46		7		(3)
Accumulated other comprehensive income, tax expense (benefit)	15		2		(1)
Net Unrealized Gain (Loss) On Securities Transferred From Available-For-Sale
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other net changes			(13,851)
Accumulated other comprehensive income, tax expense (benefit)			(4,377)
Amortization Of Held-To-Maturity Securities Transferred From Available-For-Sale Attributable To Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other net changes	1,817		542
Accumulated other comprehensive income, tax expense (benefit)	657		165
Other Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other net changes	(26)		45		(8)
Accumulated other comprehensive income, tax expense (benefit)	$ (9)		$ 15		$ (3)

[1] Certain prior year amounts have been reclassified to conform to the current year presentation. See Note 1 for additional information.