Accumulated Other Comprehensive Loss (Reclassification Out of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before tax	$ (1,743)	$ (216)	$ (5,482)	$ (759)
Other comprehensive income (loss), tax effect	412	51	1,300	179
Other comprehensive income (loss), net of tax	(1,331)	(165)	(4,182)	(580)
Investment securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net unrealized gains (losses) arising during the period, before tax	(1,757)	(161)	(5,465)	(621)
Net unrealized gains (losses) arising during the period, tax	416	38	1,295	147
Net unrealized gains (losses) arising during the period, net of tax	(1,341)	(123)	(4,170)	(474)
Net realized gains reclassified to income from continuing operations, before tax	2	44	23	82
Net realized gains reclassified to income from continuing operations, tax	0	(10)	(5)	(18)
Net realized gains reclassified to income from continuing operations, net of tax	2	34	18	64
Other comprehensive income (loss), before tax	(1,759)	(205)	(5,488)	(703)
Other comprehensive income (loss), tax effect	416	48	1,300	165
Other comprehensive income (loss), net of tax	(1,343)	(157)	(4,188)	(538)
Translation adjustments and net investment hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before tax	(11)	(4)	(13)	1
Other comprehensive income (loss), tax effect	2	1	3	0
Other comprehensive income (loss), net of tax	(9)	(3)	(10)	1
Net investment hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before tax	10	4	11	(1)
Other comprehensive income (loss), tax effect	(2)	(1)	(2)	1
Other comprehensive income (loss), net of tax	8	3	9	0
Cash flow hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net realized gains reclassified to income from continuing operations, before tax	4	12	15	55
Net realized gains reclassified to income from continuing operations, tax	(1)	(3)	(4)	(12)
Net realized gains reclassified to income from continuing operations, net of tax	3	9	11	43
Defined benefit pension plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net unrealized gains (losses) arising during the period, before tax			2	(2)
Net unrealized gains (losses) arising during the period, tax			0	1
Net unrealized gains (losses) arising during the period, net of tax			2	(1)
Net realized gains reclassified to income from continuing operations, before tax	(21)		(21)	(1)
Net realized gains reclassified to income from continuing operations, tax	5		5	0
Net realized gains reclassified to income from continuing operations, net of tax	$ (16)		(16)	(1)
Other comprehensive income (loss), before tax		(1)	23	(1)
Other comprehensive income (loss), tax effect		0	(5)	1
Other comprehensive income (loss), net of tax		$ (1)	$ 18	$ 0