Investment Securities - Held-to-Maturity Securities (Details) - USD ($) $ in Millions		Sep. 30, 2025	Dec. 31, 2024
Schedule of Held-to-Maturity Securities [Line Items]
Amortized Cost	[1]	$ 76,931	$ 78,634
Unrealized Gains		86	6
Unrealized Losses		(9,671)	(12,365)
Fair Value		67,346	66,275
U.S. Treasury and agencies
Schedule of Held-to-Maturity Securities [Line Items]
Amortized Cost		647	1,296
Unrealized Gains		0	0
Unrealized Losses		(6)	(21)
Fair Value		641	1,275
Residential mortgage-backed securities | Agency
Schedule of Held-to-Maturity Securities [Line Items]
Amortized Cost		74,326	75,392
Unrealized Gains		61	3
Unrealized Losses		(9,663)	(12,317)
Fair Value		64,724	63,078
Commercial mortgage-backed securities | Agency
Schedule of Held-to-Maturity Securities [Line Items]
Amortized Cost		1,696	1,702
Unrealized Gains		22	0
Unrealized Losses		(2)	(27)
Fair Value		1,716	1,675
Other
Schedule of Held-to-Maturity Securities [Line Items]
Amortized Cost		262	244
Unrealized Gains		3	3
Unrealized Losses		0	0
Fair Value		$ 265	$ 247

[1] Includes only collateral pledged by the Company where counterparties have the right to sell or pledge the collateral.