Accumulated Other Comprehensive Loss (Reclassification Out of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before tax	$ (1,597)	$ 247	$ (3,739)	$ (543)
Other comprehensive income (loss), tax effect	379	(58)	888	128
Other comprehensive income (loss), net of tax	(1,218)	189	(2,851)	(415)
Investment securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net unrealized gains (losses) arising during the period, before tax	(1,588)	276	(3,708)	(460)
Net unrealized gains (losses) arising during the period, tax	376	(65)	879	109
Net unrealized gains (losses) arising during the period, net of tax	(1,212)	211	(2,829)	(351)
Net realized gains reclassified to income from continuing operations, before tax	3	6	21	38
Net realized gains reclassified to income from continuing operations, tax	(1)	(1)	(5)	(8)
Net realized gains reclassified to income from continuing operations, net of tax	2	5	16	30
Other comprehensive income (loss), before tax	(1,591)	270	(3,729)	(498)
Other comprehensive income (loss), tax effect	377	(64)	884	117
Other comprehensive income (loss), net of tax	(1,214)	206	(2,845)	(381)
Translation adjustments and net investment hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before tax	(5)	2	(2)	5
Other comprehensive income (loss), tax effect	1	0	1	(1)
Other comprehensive income (loss), net of tax	(4)	2	(1)	4
Net investment hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before tax	4	(3)	1	(5)
Other comprehensive income (loss), tax effect	(1)	1	0	2
Other comprehensive income (loss), net of tax	3	(2)	1	(3)
Cash flow hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net realized gains reclassified to income from continuing operations, before tax	5	22	11	43
Net realized gains reclassified to income from continuing operations, tax	(2)	(5)	(3)	(9)
Net realized gains reclassified to income from continuing operations, net of tax	$ 3	$ 17	8	34
Defined benefit pension plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before tax			2	(2)
Other comprehensive income (loss), tax effect			0	1
Other comprehensive income (loss), net of tax			$ 2	$ (1)