Investment Securities - Components of Available-for-Sale Investment Securities Portfolio (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Investment Holdings [Line Items]
Total AFS securities	$ 28,602	$ 27,370
Unrealized Gains	0	164
Unrealized Losses	(2,533)	(313)
Available-for-sale securities	26,069	27,221
U.S. Treasury securities
Investment Holdings [Line Items]
Total AFS securities	17,206	15,799
Unrealized Gains	0	121
Unrealized Losses	(1,071)	(70)
Available-for-sale securities	16,135	15,850
U.S. agency debentures
Investment Holdings [Line Items]
Total AFS securities	120	200
Unrealized Gains	0	0
Unrealized Losses	(19)	(4)
Available-for-sale securities	101	196
Foreign government debt securities
Investment Holdings [Line Items]
Total AFS securities	1,209	61
Unrealized Gains	0	0
Unrealized Losses	(121)	0
Available-for-sale securities	1,088	61
Agency-issued MBS
Investment Holdings [Line Items]
Total AFS securities	7,701	8,786
Unrealized Gains	0	13
Unrealized Losses	(1,098)	(210)
Available-for-sale securities	6,603	8,589
Agency-issued CMO—fixed rate
Investment Holdings [Line Items]
Total AFS securities	762	988
Unrealized Gains	0	3
Unrealized Losses	(84)	(9)
Available-for-sale securities	678	982
Agency-issued CMBS
Investment Holdings [Line Items]
Total AFS securities	1,604	1,536
Unrealized Gains	0	27
Unrealized Losses	(140)	(20)
Available-for-sale securities	$ 1,464	$ 1,543

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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