AFS and HTM Debt Securities, HTM Debt Securities Purchases and Transfers (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Debt Securities, Held-to-maturity Purchase or Transfer of Investment [Abstract]
Purchases of held-to-maturity debt securities	$ 39	$ 16,574	$ 3,092	$ 76,801
Transfers from available-for-sale debt securities to held-to-maturity debt securities	5,550	0	48,591	41,298
Unrealized losses on debt securities transferred from AFS to HTM, before Tax	456		4,300	615
Securities of U.S. states and political subdivisions [Member]
Debt Securities, Held-to-maturity Purchase or Transfer of Investment [Abstract]
Purchases of held-to-maturity debt securities	0	1,409	843	4,492
Federal agency mortgage-backed securities [Member]
Debt Securities, Held-to-maturity Purchase or Transfer of Investment [Abstract]
Purchases of held-to-maturity debt securities	0	14,296	2,051	64,018
Transfers from available-for-sale debt securities to held-to-maturity debt securities	5,550	0	48,591	41,298
Non-agency mortgage-backed securities [Member]
Debt Securities, Held-to-maturity Purchase or Transfer of Investment [Abstract]
Purchases of held-to-maturity debt securities	39	30	198	114
Collateralized loan obligations [Member]
Debt Securities, Held-to-maturity Purchase or Transfer of Investment [Abstract]
Purchases of held-to-maturity debt securities	$ 0	$ 839	$ 0	$ 8,177