Accumulated Other Comprehensive Loss (Schedule of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 13,532	$ 13,984	$ 12,859	$ 17,050
Net change	(902)	(1,331)	(706)	(4,182)
Ending balance	12,825	12,434	12,825	12,434
Accumulated other comprehensive loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(3,863)	(3,009)	(4,059)	(158)
Ending balance	(4,765)	(4,340)	(4,765)	(4,340)
Unrealized losses on investment securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(3,881)	(2,940)	(4,095)	(95)
Net change	(886)	(1,343)	(672)	(4,188)
Ending balance	(4,767)	(4,283)	(4,767)	(4,283)
Translation adjustments and net investment hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	21	19	18	19
Net change	(1)	(1)	2	(1)
Ending balance	20	18	20	18
Cash flow hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(3)	27	18	35
Net change	(15)	(3)	(36)	(11)
Ending balance	(18)	24	(18)	24
Defined benefit pension plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	0	(115)	0	(117)
Net change	0	16	0	18
Ending balance	$ 0	$ (99)	$ 0	$ (99)