Accumulated Other Comprehensive Loss (Reclassification Out of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before tax	$ 371	$ (2,142)
Other comprehensive income (loss), tax effect	(88)	509
Other comprehensive (loss) income, net of tax	283	(1,633)
Investment securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net unrealized gains (losses) arising during the period, before tax	377	(2,120)
Net unrealized gains (losses) arising during the period, tax	(89)	503
Net unrealized gains (losses) arising during the period, net of tax	288	(1,617)
Net realized gains reclassified to income from continuing operations, before tax	5	18
Net realized gains reclassified to income from continuing operations, tax	(1)	(4)
Net realized gains reclassified to income from continuing operations, net of tax	4	14
Other comprehensive income (loss), before tax	372	(2,138)
Other comprehensive income (loss), tax effect	(88)	507
Other comprehensive (loss) income, net of tax	284	(1,631)
Translation adjustments and net investment hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before tax		3
Other comprehensive income (loss), tax effect		0
Other comprehensive (loss) income, net of tax		3
Net investment hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before tax		(3)
Other comprehensive income (loss), tax effect		1
Other comprehensive (loss) income, net of tax		(2)
Cash flow hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net unrealized gains (losses) arising during the period, before tax	4
Net unrealized gains (losses) arising during the period, tax	(1)
Net unrealized gains (losses) arising during the period, net of tax	3
Net realized gains reclassified to income from continuing operations, before tax	5	6
Net realized gains reclassified to income from continuing operations, tax	(1)	(1)
Net realized gains reclassified to income from continuing operations, net of tax	4	5
Other comprehensive income (loss), before tax	(1)
Other comprehensive income (loss), tax effect	0
Other comprehensive (loss) income, net of tax	$ (1)
Defined benefit pension plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net unrealized gains (losses) arising during the period, before tax		2
Net unrealized gains (losses) arising during the period, tax		0
Net unrealized gains (losses) arising during the period, net of tax		$ 2