Shareholders' Equity - Accumulated Other Comprehensive Income by Component (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended		12 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 24,750	$ 25,191	$ 26,224	$ 27,363	$ 25,191	$ 27,363	$ 27,363
Other comprehensive income (loss) before reclassifications					260	(2,573)
Increase (decrease) due to amounts reclassified from accumulated other comprehensive income					193	19
Other comprehensive income (loss)	14	439	(989)	(1,565)	453	(2,554)
Ending balance	24,204	24,750	25,767	26,224	24,204	25,767	25,191
AFS transferred to HTM					(643)		(749)
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(3,272)	(3,711)	(2,698)	(1,133)	(3,711)	(1,133)	(1,133)
Other comprehensive income (loss)	14	439	(989)	(1,565)
Ending balance	(3,258)	(3,272)	(3,687)	(2,698)	(3,258)	(3,687)	(3,711)
Net Unrealized Gains (Losses) on Cash Flow Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		(359)		(2)	(359)	(2)	(2)
Other comprehensive income (loss) before reclassifications					58	(211)
Increase (decrease) due to amounts reclassified from accumulated other comprehensive income					75	(22)
Other comprehensive income (loss)					133	(233)
Ending balance	(226)		(235)		(226)	(235)	(359)
Net Unrealized Gains (Losses) on Investment Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		(1,817)		(50)	(1,817)	(50)	(50)
Other comprehensive income (loss) before reclassifications					44	(1,816)
Increase (decrease) due to amounts reclassified from accumulated other comprehensive income					106	24
Other comprehensive income (loss)					150	(1,792)
Ending balance	(1,667)		(1,842)		(1,667)	(1,842)	(1,817)
Net Unrealized Losses on Retirement Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		(143)		(130)	(143)	(130)	(130)
Other comprehensive income (loss) before reclassifications					0	(2)
Increase (decrease) due to amounts reclassified from accumulated other comprehensive income					12	17
Other comprehensive income (loss)					12	15
Ending balance	(131)		(115)		(131)	(115)	(143)
Foreign Currency Translation
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		(1,751)		(1,019)	(1,751)	(1,019)	(1,019)
Other comprehensive income (loss) before reclassifications					207	(872)
Increase (decrease) due to amounts reclassified from accumulated other comprehensive income					0	0
Other comprehensive income (loss)					207	(872)
Ending balance	(1,544)		(1,891)		(1,544)	(1,891)	(1,751)
Net Unrealized Gains (Losses) on Hedges of Net Investments in Non-U.S. Subsidiaries
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance		$ 359		$ 68	359	68	68
Other comprehensive income (loss) before reclassifications					(49)	328
Increase (decrease) due to amounts reclassified from accumulated other comprehensive income					0	0
Other comprehensive income (loss)					(49)	328
Ending balance	$ 310		$ 396		$ 310	$ 396	$ 359