Accumulated Other Comprehensive Loss - Schedule of Reclassification Out of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before tax	$ 807	$ (1,184)	$ 555	$ (928)
Other comprehensive income (loss), tax effect	(191)	282	(132)	222
Other comprehensive income (loss), net of tax	616	(902)	423	(706)
Available-for-sale securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net unrealized gains (losses) arising during the period, before tax	772		502	(877)
Net unrealized gains (losses) arising during the period, tax	(183)		(119)	209
Net unrealized gains (losses) arising during the period, net of tax	589		383	(668)
Reclassification from AOCI, before tax	1		2	5
Reclassification from AOCI, tax	0		0	(1)
Reclassification from AOCI, net of tax	1		2	4
Other comprehensive income (loss), before tax	771	(1,163)	500	(882)
Other comprehensive income (loss), tax effect	(183)	277	(119)	210
Other comprehensive income (loss), net of tax	588	(886)	381	(672)
Held-to-maturity securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from AOCI, before tax	(23)		(65)
Reclassification from AOCI, tax	5		15
Reclassification from AOCI, net of tax	(18)		(50)
Translation adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before tax	2	(5)	(5)	1
Other comprehensive income (loss), tax effect	0	1	1	0
Other comprehensive income (loss), net of tax	2	(4)	(4)	1
Net investment hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before tax	(1)	4	5	1
Other comprehensive income (loss), tax effect	0	(1)	(1)	0
Other comprehensive income (loss), net of tax	(1)	3	4	1
Cash flow hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net unrealized gains (losses) arising during the period, before tax	8	(15)	(17)	(33)
Net unrealized gains (losses) arising during the period, tax	(2)	4	4	9
Net unrealized gains (losses) arising during the period, net of tax	6	(11)	(13)	(24)
Reclassification from AOCI, before tax	(4)	5	(7)	15
Reclassification from AOCI, tax	1	(1)	2	(3)
Reclassification from AOCI, net of tax	(3)	4	(5)	12
Other comprehensive income (loss), before tax	12	(20)	(10)	(48)
Other comprehensive income (loss), tax effect	(3)	5	2	12
Other comprehensive income (loss), net of tax	$ 9	$ (15)	$ (8)	$ (36)